A_Synopsis_of_Elementary_Results_in_Pure.pdf
A Synopsis of Elementary Results in
Pure and Applied Mathematics
Containing Propositions, Formulae, and Methods of Analysis, with Abridged Demonstrations
Wednesday, January 30, 2019
A_Synopsis_of_Elementary_Results_in_Pure
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A_Synopsis_of_Elementary_Results_in_Pure.pdf
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Tuesday, January 15, 2019
SEE Science: The Earth And Universe
1. Define satellite.
Ans: A satellite is a solid heavenly body that revolves around a planet.
2. What are artificial satellites?
Ans: The man-made satellites which keep revolving around the earth are called artificial satellites.
3. What is one light year?
Ans: The distance travelled by light in one year is called one light year.
4. Show that one light year is 9.46 × 1015m.
Ans: One light year is the distance travelled by the light in 365.25 days.
1 year = 365.25 days
1 day = 24 hours
1 hour = 60 minutes
1 minute = 60 seconds
1 year = 365.25 × 24 × 60 × 60 seconds = 31557600 seconds
Now, we know that,
Distance = velocity × time
= 3 × 108 × 31557600
= 9.46 × 1015 m
Hence, one light year is 9.46 × 1015m.
5. What are comets?
Ans: Comets are small objects that appear occasionally in the sky having a head and a luminous tail.
6. What is a comet? Describe the structure of the comet with a diagram.
Ans: The gaseous mass that revolves around the sun in highly elliptical path is called comet. It is made up of frozen gas, dust and ice. A comet consists of three main parts, the nucleus, the coma and the tail. The nucleus consists of crumbly rock particles trapped inside a frozen matter. When the comet approaches the sun, the outer layer of the nucleus begin to evaporate and it is called coma. The coma and the nucleus together are called head of the comet. As the comet approaches nearer to the sun, pressure from the solar wind elongates the coma into one or more tails.
7. What are asteroids?
Ans: The minor planets revolving around the sun in the asteroid belt between the orbits of Mars and Jupiter are called asteroids.
8. Define satellite.
Ans: A satellite is a solid heavenly body that revolves around a planet.
9. What are artificial satellites?
Ans: The man-made satellites which keep revolving around the earth are called artificial satellites.
10. What is artificial satellite? Mention any two reasons for lunching artificial satellites into the space.
Ans: Moon is the natural satellite of earth.
Manmade satellites are known as an artificial satellite.
The two reasons for launching artificial satellites into space are:
a. Weather forecast, research
b. Telecommunication
11. Mention any three reasons for launching artificial satellites in space.
Ans: The reasons for launching artificial satellites in space are:
a. To collect more and reliable information about solar system, stars, nebulas and galaxies.
b. To research the life in outer space.
c. To investigate different military and spying operation of enemies.
12. What are stars?
Ans: Stars are celestial bodies, consisting of a large, self-luminous mass of hot gas held together by their own gravity.
13. What is pulsar?
Ans: The star which revolves faster and radiates radio waves is called pulsar.
14. What is a red giant star?
Ans: A red giant star is a star with a mass like our sun that is in the last phase of its life.
15. Define supernova star.
Ans: If the mass of red giant is more than five solar masses then the difference in pressure and temperature between the core and the outer shell makes the star to explode, at this stage, it is called supernova star.
16. What is galaxy?
Ans: Galaxy is a giant assembly of billions of stars, interstellar gas and dust particles forming their own cluster in the universe all held together by gravity.
17. Write any two differences between constellation and galaxy.
Ans:
The two differences between constellation and galaxy are:
18. What is galaxy? Classify the galaxy on the basis of shape and explain about them.
Ans: The system of stars, star clusters, nebula, dust and gas which are held together by gravity is called galaxy. There are about 1012 galaxies in the universe. On the basis of the shape, galaxies are classified into irregular, spiral and elliptical galaxies.
a. Irregular galaxies
Irregular galaxies have stars in a random device by the pattern. They are the youngest galaxies. They have formed about 13.5 billion years ago. NGC 6822 and IC 1613 are the examples of irregular galaxies.
b. Spiral galaxies
Spiral galaxies are spring-shaped. They have a nucleus of bright stars and flattered arms that spiral around the nucleus. The spiral arms contain millions of stars. The Milky Way galaxy is the example of a spiral galaxy.
c. Elliptical galaxies
Elliptical galaxies are egg-shaped found largely in galaxy clusters. They contain older stars of low masses. Messier 87, Fornax and Sculptor are some examples of elliptical galaxies.
19. Define constellation.
Ans: The group of stars having a specific shape is called a constellation.
20. Write any three advantages of studying constellation.
Ans: Three advantage of studying constellation are,
a. It helps to estimate the time of night.
b. It helps scientist for dividing the sky into regions.
c. It helps in grouping the stars in the night sky.
21. Write any three superstitions related to zodiacs.
Ans: The superstitions related to zodiacs are:
a. It is believed that the attitude of a person will be accordingly the nature of their zodiac.
b. Some people select a particular day for travelling and initiating some important tasks on the basis of the position of the moon on the certain zodiac.
c. Many people prefer certain gems to put on accordingly as their zodiac or astrologist prescription, but there is no scientific reason behind it.
22. Write any three importance of zodiacs.
Ans: The importance of zodiacs are given below:
a. Some people can easily guess time and direction they want to know by observing the position of zodiacs.
b. Zodiacs are used to predict love-life, fortune, and health of people.
c. Zodiac is a great tool for better understanding the motions of the sun, the earth and the other planets.
23. Write short notes on:
Ursa Major is a constellation. It has seven stars. It is a group of seven bright stars. The constellation is identified by its question mark shape. It is the third large constellation which can be seen in April in the northern part of the sky.
b. Orion
Orion is a constellation. There are seven stars in this constellation. It looks like a hunter. It can be seen in the sky during the months of January and February in the middle sky of the northern hemisphere.
24. Life is not possible on Mars though it contains water, oxygen and carbon dioxide, gives a reason. Categorize the following heavenly bodies in term of planet, satellite, asteroids or comet:
a. Temple Tuttle-Comet
b. Sirius -Star
c. Ursa-major - Constellation
d. Neptune - Planet
The life not possible on Mars though it contains water, oxygen and carbon dioxide because of the following reasons:
i. It has a thin atmosphere which allows radiation from the sun to irradiate the surface of the planet.
ii. It is dry and barren because most of its water is locked up in the polar ice caps.
25. What is solar system?
Ans: The family of the sun which includes eight planets, their satellites, meteors, meteorites, comets, asteroids, etc. that move around the sun is called the solar system.
26. What is a planet?
Ans: A relatively small, solid celestial body moving in orbit around a star, particularly the sun is called a planet.
27. What are inner planets?
Ans: The planets which are nearer to the sun and separated from the rest of the planets by asteroid belt are called inner planets.
28. What are outer planets?
Ans: The planets which are far away from the sun and lying beyond the asteroid belt are called outer planets.
29. Mention any three application of studying the solar system.
Ans: The applications of studying solar system are:
a. It helps to estimate the distance between the planets.
b. It helps to predict the occurrence of the solar and lunar eclipse on the earth.
c. It helps to estimate the duration of the rotation and the revolution of the planets.
30. Write any three reasons for the omission of Pluto from the list of the planet in the solar system.
Ans: The Pluto has been omitted from the list of the planet in the solar system because of the following reasons:
a. Its orbit does not lie on the same plane of the orbit of the other planets.
b. It intersects the orbit of Neptune.
It is very small and very far from the sun.
31. Write any three reasons for the existence of living beings on the earth.
Ans: The reasons for the existence of living beings on the earth are:
a. The earth is at a suitable distance from the sun.
b. The earth has atmosphere and all the gases required for the life of creatures.
c. The earth has water which is the most important chemical necessary for life.
32. Write any three features of the planet Saturn.
Ans: The features of the planet Saturn are:
a. It has a brightest concentric ring which is made up of ice, dust particles which revolves around it.
b. It is the second largest planet in the solar system.
c. It has 23 satellites.
33. Describe in brief about the structure and shape of the solar system with diagram.
Ans: The celestial bodies including planets, satellites, comets, etc. which revolve around the sun form the solar system. It consists of eight planets their satellites, heavenly bodies like a meteor, meteorites, plasma, asteroids, comets, charged particles and dust particles. All the member of the solar family revolves around the sun in their orbit due to the gravitational attraction between the sun and the other bodies. Asteroids are also found in the solar system and they are concentrated between the orbits of the Mars and Jupiter. The four planets i.e. Mercury, Venus, Earth and Mars are inner planets.
34. Write short notes on:
Mercury is the closest planet to the sun. It takes about 59 days to complete one rotation on its axis and 88 days to complete one revolution around the sun. It does not have atmosphere and satellite. Its temperature varies from -170°C to 427°C. The diameter of the Mercury is 4880 km. The phases of the Mercury can be seen by using a telescope.
b. Mars
Mars is the fourth nearest planet from the sun. Due to the presence of limonite, it is red in colour. So, it is called red planet and can be seen easily from the earth. It takes 24 hr 37 min to complete one rotation and 687 days to complete one revolution around the sun. Its diameter is 6,742km. It consists of two satellites. They are diemos and phobos.
35. What is a satellite? Mention its types and explain.
Ans:
A satellite is a heavenly body that revolves around the planet in their own orbit. They do not have their own light. They reflect the light rays coming from the sun.
There are two different types of satellites. They are natural satellite and artificial satellite.
a. Natural satellite
Natural satellites are those members of the solar system which revolve around the planets in their elliptical orbits. They do not have their own light. They reflect the light from the sun. They are called the moon.
b. Artificial satellite
The satellite that is made on the earth which continuously revolves around the earth or other heavenly body is called an artificial satellite. The orbit of artificial satellites is elliptical and characterized by three parameters apogee, perigee and inclination.
36. What is solar wind? Mention any three features of the sun.
Ans: The solar wind is a stream of energized, charged particles, primarily electrons and protons, flowing outward from the sun. It is caused by the hot solar corona, which is the outermost layer of the solar atmosphere.
The features of the sun are given below:
i. The sun is the medium-sized star whose diameter is about 1,392,000 km.
ii. The sun’s mass consists of about 75% of hydrogen and about 25% of helium.
iii. The sun produces most of the energy in the core by the means of nuclear fusion.
37. What is a black hole?
Ans: A black hole is a heavenly body or point in space which has infinite density and gravity such that even light falling on it can’t escape.
38. Define meteorites.
Ans: The meteor which reaches the earth’s surface before they completely burn is called meteorites.
39. What are meteors?
Ans: Meteors are the bright streak of light seen for a short duration of time in the sky on a clear night.
40. Define meteorites.
Ans: The unburned masses of the meteors that reach the earth’s surface are called meteorites.
41. Define stony meteorites.
Ans: The meteorites which contain more silica and less iron and magnesium are called stony meteorites.
42. Write short notes on meteor and meteorites and write the types of meteorite.
Ans:
Meteor: A meteor is a bright streak of light seen for a short duration in the sky on a clear night. It is also called shooting star or falling star because it looks like a star falling from one direction to the other direction to the other in the sky.
Meteorites: Some meteors are larger and do not burn completely as they travel through the atmosphere and reach the surface of the planets or moon due to gravity. These are called meteorites. On the basis of the nature of particles present in the meteorites, they are of three types. They are:
i. Stony: That meteorite which consists of more amounts of silica and less amount of iron is called stony meteorites.
ii. Irony: That meteorite which consists of more amounts of iron and less amount of silica is irony meteorites.
iii. Stony-iron: Those meteorites which consist of an equal amount of iron and silica is called stony-iron meteorites.
43. Describe in brief about Milky Way galaxy.
Ans: The Milky Way galaxy is a spiral galaxy that contains our solar system. The main body of this galaxy is a disc-like shape. Its central part is thicker and its edge is thinner. It is about 2.5 × 104light years away from the galactic centre. It is estimated that there might be 1011 stars in the Milky Way galaxy and its total mass is about 1.33 × 1011 times more than that of the sun.
Ans: A satellite is a solid heavenly body that revolves around a planet.
2. What are artificial satellites?
Ans: The man-made satellites which keep revolving around the earth are called artificial satellites.
3. What is one light year?
Ans: The distance travelled by light in one year is called one light year.
4. Show that one light year is 9.46 × 1015m.
Ans: One light year is the distance travelled by the light in 365.25 days.
1 year = 365.25 days
1 day = 24 hours
1 hour = 60 minutes
1 minute = 60 seconds
1 year = 365.25 × 24 × 60 × 60 seconds = 31557600 seconds
Now, we know that,
Distance = velocity × time
= 3 × 108 × 31557600
= 9.46 × 1015 m
Hence, one light year is 9.46 × 1015m.
5. What are comets?
Ans: Comets are small objects that appear occasionally in the sky having a head and a luminous tail.
6. What is a comet? Describe the structure of the comet with a diagram.
Ans: The gaseous mass that revolves around the sun in highly elliptical path is called comet. It is made up of frozen gas, dust and ice. A comet consists of three main parts, the nucleus, the coma and the tail. The nucleus consists of crumbly rock particles trapped inside a frozen matter. When the comet approaches the sun, the outer layer of the nucleus begin to evaporate and it is called coma. The coma and the nucleus together are called head of the comet. As the comet approaches nearer to the sun, pressure from the solar wind elongates the coma into one or more tails.
7. What are asteroids?
Ans: The minor planets revolving around the sun in the asteroid belt between the orbits of Mars and Jupiter are called asteroids.
8. Define satellite.
Ans: A satellite is a solid heavenly body that revolves around a planet.
9. What are artificial satellites?
Ans: The man-made satellites which keep revolving around the earth are called artificial satellites.
10. What is artificial satellite? Mention any two reasons for lunching artificial satellites into the space.
Ans: Moon is the natural satellite of earth.
Manmade satellites are known as an artificial satellite.
The two reasons for launching artificial satellites into space are:
a. Weather forecast, research
b. Telecommunication
11. Mention any three reasons for launching artificial satellites in space.
Ans: The reasons for launching artificial satellites in space are:
a. To collect more and reliable information about solar system, stars, nebulas and galaxies.
b. To research the life in outer space.
c. To investigate different military and spying operation of enemies.
12. What are stars?
Ans: Stars are celestial bodies, consisting of a large, self-luminous mass of hot gas held together by their own gravity.
13. What is pulsar?
Ans: The star which revolves faster and radiates radio waves is called pulsar.
14. What is a red giant star?
Ans: A red giant star is a star with a mass like our sun that is in the last phase of its life.
15. Define supernova star.
Ans: If the mass of red giant is more than five solar masses then the difference in pressure and temperature between the core and the outer shell makes the star to explode, at this stage, it is called supernova star.
16. What is galaxy?
Ans: Galaxy is a giant assembly of billions of stars, interstellar gas and dust particles forming their own cluster in the universe all held together by gravity.
17. Write any two differences between constellation and galaxy.
Ans:
The two differences between constellation and galaxy are:
| Constellation | Galaxy |
| 1. A group of stars with the definite pattern seen in the night sky is a constellation. | 1. A collection of trillions of stars, gases and dust particles is called a galaxy. |
| 2. 88 constellations have been discovered so far. Eg: Ursa Major | 2. There are about one hundred billion galaxies in the observable universe. Eg: The Milky Way |
18. What is galaxy? Classify the galaxy on the basis of shape and explain about them.
Ans: The system of stars, star clusters, nebula, dust and gas which are held together by gravity is called galaxy. There are about 1012 galaxies in the universe. On the basis of the shape, galaxies are classified into irregular, spiral and elliptical galaxies.
a. Irregular galaxies
Irregular galaxies have stars in a random device by the pattern. They are the youngest galaxies. They have formed about 13.5 billion years ago. NGC 6822 and IC 1613 are the examples of irregular galaxies.
b. Spiral galaxies
Spiral galaxies are spring-shaped. They have a nucleus of bright stars and flattered arms that spiral around the nucleus. The spiral arms contain millions of stars. The Milky Way galaxy is the example of a spiral galaxy.
c. Elliptical galaxies
Elliptical galaxies are egg-shaped found largely in galaxy clusters. They contain older stars of low masses. Messier 87, Fornax and Sculptor are some examples of elliptical galaxies.
19. Define constellation.
Ans: The group of stars having a specific shape is called a constellation.
20. Write any three advantages of studying constellation.
Ans: Three advantage of studying constellation are,
a. It helps to estimate the time of night.
b. It helps scientist for dividing the sky into regions.
c. It helps in grouping the stars in the night sky.
21. Write any three superstitions related to zodiacs.
Ans: The superstitions related to zodiacs are:
a. It is believed that the attitude of a person will be accordingly the nature of their zodiac.
b. Some people select a particular day for travelling and initiating some important tasks on the basis of the position of the moon on the certain zodiac.
c. Many people prefer certain gems to put on accordingly as their zodiac or astrologist prescription, but there is no scientific reason behind it.
22. Write any three importance of zodiacs.
Ans: The importance of zodiacs are given below:
a. Some people can easily guess time and direction they want to know by observing the position of zodiacs.
b. Zodiacs are used to predict love-life, fortune, and health of people.
c. Zodiac is a great tool for better understanding the motions of the sun, the earth and the other planets.
23. Write short notes on:
a. Ursa major
b. Orion
Ans: a. Ursa majorb. Orion
Ursa Major is a constellation. It has seven stars. It is a group of seven bright stars. The constellation is identified by its question mark shape. It is the third large constellation which can be seen in April in the northern part of the sky.
b. Orion
Orion is a constellation. There are seven stars in this constellation. It looks like a hunter. It can be seen in the sky during the months of January and February in the middle sky of the northern hemisphere.
24. Life is not possible on Mars though it contains water, oxygen and carbon dioxide, gives a reason. Categorize the following heavenly bodies in term of planet, satellite, asteroids or comet:
a. Temple Tuttle
b. Sirius
c. Ursa-major
d. Neptune
Ans: b. Sirius
c. Ursa-major
d. Neptune
a. Temple Tuttle-Comet
b. Sirius -Star
c. Ursa-major - Constellation
d. Neptune - Planet
The life not possible on Mars though it contains water, oxygen and carbon dioxide because of the following reasons:
i. It has a thin atmosphere which allows radiation from the sun to irradiate the surface of the planet.
ii. It is dry and barren because most of its water is locked up in the polar ice caps.
25. What is solar system?
Ans: The family of the sun which includes eight planets, their satellites, meteors, meteorites, comets, asteroids, etc. that move around the sun is called the solar system.
26. What is a planet?
Ans: A relatively small, solid celestial body moving in orbit around a star, particularly the sun is called a planet.
27. What are inner planets?
Ans: The planets which are nearer to the sun and separated from the rest of the planets by asteroid belt are called inner planets.
28. What are outer planets?
Ans: The planets which are far away from the sun and lying beyond the asteroid belt are called outer planets.
29. Mention any three application of studying the solar system.
Ans: The applications of studying solar system are:
a. It helps to estimate the distance between the planets.
b. It helps to predict the occurrence of the solar and lunar eclipse on the earth.
c. It helps to estimate the duration of the rotation and the revolution of the planets.
30. Write any three reasons for the omission of Pluto from the list of the planet in the solar system.
Ans: The Pluto has been omitted from the list of the planet in the solar system because of the following reasons:
a. Its orbit does not lie on the same plane of the orbit of the other planets.
b. It intersects the orbit of Neptune.
It is very small and very far from the sun.
31. Write any three reasons for the existence of living beings on the earth.
Ans: The reasons for the existence of living beings on the earth are:
a. The earth is at a suitable distance from the sun.
b. The earth has atmosphere and all the gases required for the life of creatures.
c. The earth has water which is the most important chemical necessary for life.
32. Write any three features of the planet Saturn.
Ans: The features of the planet Saturn are:
a. It has a brightest concentric ring which is made up of ice, dust particles which revolves around it.
b. It is the second largest planet in the solar system.
c. It has 23 satellites.
33. Describe in brief about the structure and shape of the solar system with diagram.
Ans: The celestial bodies including planets, satellites, comets, etc. which revolve around the sun form the solar system. It consists of eight planets their satellites, heavenly bodies like a meteor, meteorites, plasma, asteroids, comets, charged particles and dust particles. All the member of the solar family revolves around the sun in their orbit due to the gravitational attraction between the sun and the other bodies. Asteroids are also found in the solar system and they are concentrated between the orbits of the Mars and Jupiter. The four planets i.e. Mercury, Venus, Earth and Mars are inner planets.
34. Write short notes on:
a. Mercury
b. Mars
Ans: a. Mercuryb. Mars
Mercury is the closest planet to the sun. It takes about 59 days to complete one rotation on its axis and 88 days to complete one revolution around the sun. It does not have atmosphere and satellite. Its temperature varies from -170°C to 427°C. The diameter of the Mercury is 4880 km. The phases of the Mercury can be seen by using a telescope.
b. Mars
Mars is the fourth nearest planet from the sun. Due to the presence of limonite, it is red in colour. So, it is called red planet and can be seen easily from the earth. It takes 24 hr 37 min to complete one rotation and 687 days to complete one revolution around the sun. Its diameter is 6,742km. It consists of two satellites. They are diemos and phobos.
35. What is a satellite? Mention its types and explain.
Ans:
A satellite is a heavenly body that revolves around the planet in their own orbit. They do not have their own light. They reflect the light rays coming from the sun.
There are two different types of satellites. They are natural satellite and artificial satellite.
a. Natural satellite
Natural satellites are those members of the solar system which revolve around the planets in their elliptical orbits. They do not have their own light. They reflect the light from the sun. They are called the moon.
b. Artificial satellite
The satellite that is made on the earth which continuously revolves around the earth or other heavenly body is called an artificial satellite. The orbit of artificial satellites is elliptical and characterized by three parameters apogee, perigee and inclination.
36. What is solar wind? Mention any three features of the sun.
Ans: The solar wind is a stream of energized, charged particles, primarily electrons and protons, flowing outward from the sun. It is caused by the hot solar corona, which is the outermost layer of the solar atmosphere.
The features of the sun are given below:
i. The sun is the medium-sized star whose diameter is about 1,392,000 km.
ii. The sun’s mass consists of about 75% of hydrogen and about 25% of helium.
iii. The sun produces most of the energy in the core by the means of nuclear fusion.
37. What is a black hole?
Ans: A black hole is a heavenly body or point in space which has infinite density and gravity such that even light falling on it can’t escape.
38. Define meteorites.
Ans: The meteor which reaches the earth’s surface before they completely burn is called meteorites.
39. What are meteors?
Ans: Meteors are the bright streak of light seen for a short duration of time in the sky on a clear night.
40. Define meteorites.
Ans: The unburned masses of the meteors that reach the earth’s surface are called meteorites.
41. Define stony meteorites.
Ans: The meteorites which contain more silica and less iron and magnesium are called stony meteorites.
42. Write short notes on meteor and meteorites and write the types of meteorite.
Ans:
Meteor: A meteor is a bright streak of light seen for a short duration in the sky on a clear night. It is also called shooting star or falling star because it looks like a star falling from one direction to the other direction to the other in the sky.
Meteorites: Some meteors are larger and do not burn completely as they travel through the atmosphere and reach the surface of the planets or moon due to gravity. These are called meteorites. On the basis of the nature of particles present in the meteorites, they are of three types. They are:
i. Stony: That meteorite which consists of more amounts of silica and less amount of iron is called stony meteorites.
ii. Irony: That meteorite which consists of more amounts of iron and less amount of silica is irony meteorites.
iii. Stony-iron: Those meteorites which consist of an equal amount of iron and silica is called stony-iron meteorites.
43. Describe in brief about Milky Way galaxy.
Ans: The Milky Way galaxy is a spiral galaxy that contains our solar system. The main body of this galaxy is a disc-like shape. Its central part is thicker and its edge is thinner. It is about 2.5 × 104light years away from the galactic centre. It is estimated that there might be 1011 stars in the Milky Way galaxy and its total mass is about 1.33 × 1011 times more than that of the sun.
Saturday, January 5, 2019
SEE Science: Climate Change And Atmosphere
1. What is Kyoto protocol? Describe in brief.
Ans: Kyoto protocol was adopted in December 1997 A.D. Its main objective is to reduce climate change and production of greenhouse gases to control global warming. The protocol makes 36 developed countries of the world to reduce the emission of green house gases by 5.25% by 2012 A.D. from their industries. The provision is now extended for 2020 A.D. by the convention held in 2012 A.D. at Doha. The Kyoto protocol encourages developed and developing countries to work under the three market level mechanisms to meet their green house gas emission target. They are international emission trading, joint implementation and clean development mechanism.
2. Following are the findings in a study done on the earth environment:
a. The main cause of the above finding is depletion of the ozone layer.
b. The production of chlorofluorocarbon (CFCs), methyl chloroform, carbon tetrachloride, nitrogenous fertilizers and fossil fuel should be reduced.
c. The depletion of the ozone layer causes skin inflammation, different types of cancer, cataract, loss of immunity, etc. It also affects DNA which may cause mutation.
d. Due to ozone layer depletion, more ultraviolet rays and more radiation of the sun enter the surface of the earth which results in the increase of the temperature of the earth.
3. Explain in brief about any four national efforts to minimize the climate change.
Ans: The national efforts to minimize the climate change are:
a. National Communication Report
In this report, Nepal has mentioned the impacts of climate change, additional ways to the change and various policies and laws to be implemented to combat climate change.
b. Climate Change Policy, 2067
Global warming is the result of climate change. It adversely affects human health, agriculture, forest and various human-related aspects. In this regard, the climate change policy has been formulated to create awareness among the people and develop adaption.
c. National Adaption Program
National adaption program was prepared in the year 2010 by the government of Nepal. It mainly evaluates the risk of climate change. It has launched altogether 250 programmes integrating into 9 different sectors.
d. Other programs
Other programs include programs related to improved chimneys of brick factories, improved stove, use of biogas, a pre-information system about a natural disaster, etc.
4. Explain in brief about any four international efforts to minimize the climate change.
Ans: The international efforts to minimize the climate change are:
a. The United Nation Framework Convention on Climate Change (UNFCCC)
It was held in the year 1992 in Rio de Jene Rio. This conference addressed various aspects like increasing environmental pollution, sustainable development program, etc.
b. UN Climate Change Conference
The UN conference on climate change has been conducted 19 times till 2013 A.D to inform the works and programs conducted in a country to other member countries related to climate change.
c. Agenda 21
This action plan was formulated on the basis of the slogan “think globally and act locally” to conserve the environment and ensure sustainable development.
d. Intergovernmental Forum
It consists of the scientific, technical and socio-economical information to understand the risk of human-caused due to climate change, adverse effects of climate change and the mitigating measure.
5. What is Kyoto protocol? Describe in brief.
Ans: Kyoto protocol was adopted in December 1997 A.D. Its main objective is to reduce climate change and production of greenhouse gases to control global warming. The protocol makes 36 developed countries of the world to reduce the emission of green house gases by 5.25% by 2012 A.D. from their industries. The provision is now extended for 2020 A.D. by the convention held in 2012 A.D. at Doha. The Kyoto protocol encourages developed and developing countries to work under the three market level mechanisms to meet their green house gas emission target. They are international emission trading, joint implementation and clean development mechanism.
6. Following are the findings in a study done on the earth environment:
b. The production of chlorofluorocarbon (CFCs), methyl chloroform, carbon tetrachloride, nitrogenous fertilizers and fossil fuel should be reduced.
c. The depletion of the ozone layer causes skin inflammation, different types of cancer, cataract, loss of immunity, etc. It also affects DNA which may cause mutation.
d. Due to ozone layer depletion, more ultraviolet rays and more radiation of the sun enter the surface of the earth which results in the increase of the temperature of the earth.
7. Define fog.
Ans: The minute water particles suspended in air near the surface of the earth is called fog.
8. What is global warming?
Ans: A gradual increase in the average temperature of the earth is called global warming.
9. Consequences like skin burn and skin cancer were observed when sunbathe is taken on earth surface. Answer the following questions on the basis of it:
b. We should conserve the ozone layer to control this situation.
c. Due to ozone layer depletion, more ultraviolet rays and more radiation of the sun enter the surface of the earth which results in the increase of the temperature of the earth.
10. How does chlorofluorocarbon deplete the ozone layer? Explain with a chemical equation.
Ans: The depletion of ozone layer is the formation of a hole in it or gradual thinning of this layer. Depletion of the ozone layer is caused due to the entry of chemicals like chlorofluorocarbon (CFCs), methyl chloroform, carbon tetrachloride, etc. into the atmosphere. CFCs are the non-toxic, non-inflammable and cheap chemicals used as a refrigerant. When CFCs are reached into the atmosphere they deplete the ozone layer. In the presence of UV rays, CF2Cl2 splits into ClO and O2. ClO breaks into Cl and O by the UV rays. The Cl and O participate in a chain reaction and cause ozone layer depletion.
The following chemical equation shows the depletion of the ozone layer.
CF 2 Cl 2 UV rays → CF 2 Cl + Cl
Cl + O 3 UV rays → ClO + O 2
ClO UV ray → Cl + O
O + O 3 UV rays → O 2 + O 2
11. Write any three uses of chlorofluorocarbon.
Ans: The uses of chlorofluorocarbon are:
a. They are used as refrigerants.
b. They are used in the manufacturing of blowing agents for foams and packing materials.
c. They are used in an aerosol spray can.
12. What is the ozone layer? Why is it called protective layer? How is the thickness of the ozone layer decreased? Human beings are responsible for the ozone layer depletion, how?
Ans: The ozone layer is a region of earth’s stratosphere that absorbs most of the sun’s ultraviolet radiation. It contains high concentrations of ozone. Ozone consists of three atoms of oxygen.
The ozone layer is called protective layer because it absorbs 99% of ultraviolet rays and prevents them from entering into earth surface. It protects us from the diseases like blindness, skin cancer, etc. caused due to harmful rays.
The thickness of the ozone layer is decreased due to the reaction of chemicals like chlorofluorocarbon (CFCs), methyl chloroform, carbon tetrachloride with ozone.
Human beings use different appliances which use CFCs, nitrogenous fertilizers, fossils fuel which deplete the ozone layer.
13. Define acid rain.
Ans: The rain containing acids that are formed in the atmosphere when industrial gas emissions combine with water is called acid rain.
14. How does acid rain occur due to the industrial gases? Explain with chemical equation.
Ans: The various harmful gases like carbon dioxide, carbon monoxide, sulphur dioxide, nitrogen oxide, etc. which are produced by the industries are called industrial gases.
Acid rain is a rain or any other form of precipitation that is usually acidic. It is caused by the emission of sulphur dioxide and nitrogen dioxide, which react with the water molecules in the atmosphere to produce acids. When the gases from the industries reached the atmosphere and react with rainwater, they form respective acids. And hence cause acid rain.
a. When nitrogen dioxide reacts with rainwater in the atmosphere it forms nitric acid.
Ans: The envelope of air that surrounds the earth is called atmosphere.
16. What is troposphere?
Ans: The lowermost layer of atmosphere near the surface of the earth is called troposphere.
17. What is stratosphere?
Ans: The layer of atmosphere which lies just above the troposphere is called the stratosphere.
18. What is mesosphere?
Ans: The layer of atmosphere which lies just above the stratosphere is called mesosphere.
19. What is thermosphere?
Ans: The layer of atmosphere which starts from mesosphere and ends at exosphere is called thermosphere.
20. What is exosphere?
Ans: The outermost layer of the atmosphere is called exosphere.
21. What is ozone?
Ans: Ozone is the molecule of three oxygen atoms which forms ozone-layer in the upper part of the stratosphere.
22. What is green house effect?
Ans: Greenhouse effect is the warming of the earth’s surface that occurs due to the trapping of the sun’s heat by the earth’s atmosphere.
23. What are industrial gases?
Ans: The different gases like sulphur dioxide, carbon dioxide, nitrous oxide, etc. which are produced by industries are called industrial gases.
24. Define chlorofluorocarbon.
Ans: Chlorofluorocarbon is a chemical compound containing carbon, hydrogen, chlorine and fluorine.
25. Define ozone hole.
Ans: An ozone hole is the region of space in the stratosphere where the amount of ozone content has been reduced drastically.
26. Define tropopause.
Ans: The upper boundary of the troposphere is called tropopause.
27. Define mesopause.
Ans: The uppermost layer of the mesosphere is called mesopause.
28. Define stratopause.
Ans: The upper boundary of stratosphere is called stratopause.
29. What is a green house?
Ans: Greenhouse is a building made up of green glasses which can trap the solar radiation in it.
30. Define ozone depletion.
Ans: The loss or damage of ozone in the atmosphere is called ozone depletion.
31. What do you mean by greenhouse gases?
Ans: The gases which are responsible for greenhouse effect are called greenhouse gases.
32. How is the amount of the ozone molecules being balanced naturally?
Ans: Ozone is created primarily in the stratosphere by ultraviolet radiation. When high-energy ultraviolet rays strike on ordinary molecules, they split the molecules into two single oxygen atoms, known as atomic oxygen. A freed oxygen atom then combines with another oxygen molecule to form a molecule of ozone. In this way the amount of the ozone molecules is balanced naturally.
33. Write any three importance of ozone layer?
Ans: The importance of the ozone layer are:
a. It absorbs 99% of ultraviolet rays and prevents them from entering into earth surface.
b. It helps to maintain a suitable temperature of the earth.
c. It protects us from the diseases like blindness, skin cancer, etc.
34. Write any three effects seen in human health due to the depletion of ozone layer.
Ans: The effects seen in human health due to the depletion of ozone layer are:
a. It may cause skin inflammation.
b. Different types of cancers, cataract, loss of immunity, etc. are caused due to it.
c. It also may affect DNA which may cause mutation.
35. Describe in short about the causes of depletion of ozone layer.
Ans: The depletion of ozone layer is the formation of a hole in it or gradual thinning of this layer. Depletion of the ozone layer is caused due to the entry of chemicals like chlorofluorocarbon (CFCs), methyl chloroform, carbon tetrachloride, etc. into the atmosphere. CFCs are the non-toxic, non-inflammable and cheap chemicals used as refrigerant When CFCs are reached into the atmosphere they deplete the ozone layer. In the presence of UV rays, CF2Cl2 splits into ClO and O2. ClO breaks into Cl and O by the UV rays. The Cl and O participate in a chain reaction and cause ozone layer depletion.
36. Write any three characteristics of chlorofluorocarbon.
Ans: The characteristics of chlorofluorocarbon are:
a. Chlorofluorocarbons are non-toxic, non-flammable chemicals.
b. They are used in the manufacturing of aerosols, blowing agents for foams and packing materials, as solvents, and as refrigerants.
c. They are responsible for ozone layer depletion.
37. Write down any three features of troposphere.
Ans: The features of the troposphere are:
a. It extends from 8-10 km at the poles and up to 16 km at the equatorial.
b. It contains oxygen, nitrogen, carbon dioxide, water vapour and dust particles.
c. It is highly affected by human activities.
38. Write any three effects of the increasing quantity of carbon dioxide gas in atmosphere.
Ans: The effects of increasing quantity of carbon dioxide gas in the atmosphere are:
i. The temperature of the earth will increase.
ii. More water vapour evaporates into the atmosphere which increases greenhouse heating.
iii. The carbon dioxide that dissolves in the ocean through direct chemical exchange creates carbonic acid which increases the acidity of the water.
39. Write short notes on:
The layer of atmosphere above the troposphere is called the stratosphere. It is extended up to 16 km to 50 km above the earth’s surface. This region is also called ozonosphere. The ozone layer protects us from the harmful effects of ultraviolet rays of the sun.
b. Mesosphere
The layer of atmosphere above the stratosphere is called mesosphere. It is extended up to 50 km to 80 km above the earth’s surface. It consists of nitrogen, nascent oxygen and oxygen. This layer is the coldest layer of the atmosphere. It has strong wind which blows eastward in the winter and westward in the summer.
40. Write in brief about the climate change policy, 2067.
Ans: Global warming is the result of climate change. It adversely affects human health, agriculture, forest and various human-related aspects. In this regard, the climate change policy has been formulated to create awareness among the people and develop adaption.
40. Draw a labeled diagram of different layers of earth’s atmosphere.
Ans:
Ans: Kyoto protocol was adopted in December 1997 A.D. Its main objective is to reduce climate change and production of greenhouse gases to control global warming. The protocol makes 36 developed countries of the world to reduce the emission of green house gases by 5.25% by 2012 A.D. from their industries. The provision is now extended for 2020 A.D. by the convention held in 2012 A.D. at Doha. The Kyoto protocol encourages developed and developing countries to work under the three market level mechanisms to meet their green house gas emission target. They are international emission trading, joint implementation and clean development mechanism.
2. Following are the findings in a study done on the earth environment:
The temperature on the earth is increasing. The number of amphibians is decreasing. Human beings are suffering from cataract and skin cancer. Answer the following on the basis of the above facts:
a. What is the cause of the above findings?
b. What is to be done to be safe from the above conditions?
c. Write down its more harmful effects to the human health.
d. What happens to the environmental temperature at this condition?
Ans: a. What is the cause of the above findings?
b. What is to be done to be safe from the above conditions?
c. Write down its more harmful effects to the human health.
d. What happens to the environmental temperature at this condition?
a. The main cause of the above finding is depletion of the ozone layer.
b. The production of chlorofluorocarbon (CFCs), methyl chloroform, carbon tetrachloride, nitrogenous fertilizers and fossil fuel should be reduced.
c. The depletion of the ozone layer causes skin inflammation, different types of cancer, cataract, loss of immunity, etc. It also affects DNA which may cause mutation.
d. Due to ozone layer depletion, more ultraviolet rays and more radiation of the sun enter the surface of the earth which results in the increase of the temperature of the earth.
3. Explain in brief about any four national efforts to minimize the climate change.
Ans: The national efforts to minimize the climate change are:
a. National Communication Report
In this report, Nepal has mentioned the impacts of climate change, additional ways to the change and various policies and laws to be implemented to combat climate change.
b. Climate Change Policy, 2067
Global warming is the result of climate change. It adversely affects human health, agriculture, forest and various human-related aspects. In this regard, the climate change policy has been formulated to create awareness among the people and develop adaption.
c. National Adaption Program
National adaption program was prepared in the year 2010 by the government of Nepal. It mainly evaluates the risk of climate change. It has launched altogether 250 programmes integrating into 9 different sectors.
d. Other programs
Other programs include programs related to improved chimneys of brick factories, improved stove, use of biogas, a pre-information system about a natural disaster, etc.
4. Explain in brief about any four international efforts to minimize the climate change.
Ans: The international efforts to minimize the climate change are:
a. The United Nation Framework Convention on Climate Change (UNFCCC)
It was held in the year 1992 in Rio de Jene Rio. This conference addressed various aspects like increasing environmental pollution, sustainable development program, etc.
b. UN Climate Change Conference
The UN conference on climate change has been conducted 19 times till 2013 A.D to inform the works and programs conducted in a country to other member countries related to climate change.
c. Agenda 21
This action plan was formulated on the basis of the slogan “think globally and act locally” to conserve the environment and ensure sustainable development.
d. Intergovernmental Forum
It consists of the scientific, technical and socio-economical information to understand the risk of human-caused due to climate change, adverse effects of climate change and the mitigating measure.
5. What is Kyoto protocol? Describe in brief.
Ans: Kyoto protocol was adopted in December 1997 A.D. Its main objective is to reduce climate change and production of greenhouse gases to control global warming. The protocol makes 36 developed countries of the world to reduce the emission of green house gases by 5.25% by 2012 A.D. from their industries. The provision is now extended for 2020 A.D. by the convention held in 2012 A.D. at Doha. The Kyoto protocol encourages developed and developing countries to work under the three market level mechanisms to meet their green house gas emission target. They are international emission trading, joint implementation and clean development mechanism.
6. Following are the findings in a study done on the earth environment:
The temperature on the earth is increasing. The number of amphibians is decreasing. Human beings are suffering from cataract and skin cancer. Answer the following on the basis of the above facts:
a. What is the cause of the above findings?
b. What is to be done to be safe from the above conditions?
c. Write down its more harmful effects to the human health.
d. What happens to the environmental temperature at this condition?
Ans: a. The main cause of the above finding is depletion of the ozone layer.a. What is the cause of the above findings?
b. What is to be done to be safe from the above conditions?
c. Write down its more harmful effects to the human health.
d. What happens to the environmental temperature at this condition?
b. The production of chlorofluorocarbon (CFCs), methyl chloroform, carbon tetrachloride, nitrogenous fertilizers and fossil fuel should be reduced.
c. The depletion of the ozone layer causes skin inflammation, different types of cancer, cataract, loss of immunity, etc. It also affects DNA which may cause mutation.
d. Due to ozone layer depletion, more ultraviolet rays and more radiation of the sun enter the surface of the earth which results in the increase of the temperature of the earth.
7. Define fog.
Ans: The minute water particles suspended in air near the surface of the earth is called fog.
8. What is global warming?
Ans: A gradual increase in the average temperature of the earth is called global warming.
9. Consequences like skin burn and skin cancer were observed when sunbathe is taken on earth surface. Answer the following questions on the basis of it:
a. What is the cause of it?
b. What is to be done to control this situation?
c. What happen to the environmental temperature at this condition?
Ans: a. It is due to the depletion of ozone layer depletion.b. What is to be done to control this situation?
c. What happen to the environmental temperature at this condition?
b. We should conserve the ozone layer to control this situation.
c. Due to ozone layer depletion, more ultraviolet rays and more radiation of the sun enter the surface of the earth which results in the increase of the temperature of the earth.
10. How does chlorofluorocarbon deplete the ozone layer? Explain with a chemical equation.
Ans: The depletion of ozone layer is the formation of a hole in it or gradual thinning of this layer. Depletion of the ozone layer is caused due to the entry of chemicals like chlorofluorocarbon (CFCs), methyl chloroform, carbon tetrachloride, etc. into the atmosphere. CFCs are the non-toxic, non-inflammable and cheap chemicals used as a refrigerant. When CFCs are reached into the atmosphere they deplete the ozone layer. In the presence of UV rays, CF2Cl2 splits into ClO and O2. ClO breaks into Cl and O by the UV rays. The Cl and O participate in a chain reaction and cause ozone layer depletion.
The following chemical equation shows the depletion of the ozone layer.
11. Write any three uses of chlorofluorocarbon.
Ans: The uses of chlorofluorocarbon are:
a. They are used as refrigerants.
b. They are used in the manufacturing of blowing agents for foams and packing materials.
c. They are used in an aerosol spray can.
12. What is the ozone layer? Why is it called protective layer? How is the thickness of the ozone layer decreased? Human beings are responsible for the ozone layer depletion, how?
Ans: The ozone layer is a region of earth’s stratosphere that absorbs most of the sun’s ultraviolet radiation. It contains high concentrations of ozone. Ozone consists of three atoms of oxygen.
The ozone layer is called protective layer because it absorbs 99% of ultraviolet rays and prevents them from entering into earth surface. It protects us from the diseases like blindness, skin cancer, etc. caused due to harmful rays.
The thickness of the ozone layer is decreased due to the reaction of chemicals like chlorofluorocarbon (CFCs), methyl chloroform, carbon tetrachloride with ozone.
Human beings use different appliances which use CFCs, nitrogenous fertilizers, fossils fuel which deplete the ozone layer.
13. Define acid rain.
Ans: The rain containing acids that are formed in the atmosphere when industrial gas emissions combine with water is called acid rain.
14. How does acid rain occur due to the industrial gases? Explain with chemical equation.
Ans: The various harmful gases like carbon dioxide, carbon monoxide, sulphur dioxide, nitrogen oxide, etc. which are produced by the industries are called industrial gases.
Acid rain is a rain or any other form of precipitation that is usually acidic. It is caused by the emission of sulphur dioxide and nitrogen dioxide, which react with the water molecules in the atmosphere to produce acids. When the gases from the industries reached the atmosphere and react with rainwater, they form respective acids. And hence cause acid rain.
a. When nitrogen dioxide reacts with rainwater in the atmosphere it forms nitric acid.
4NO2 + 2H2O + O2 à 4HNO3
b. When sulphur dioxide reacts with rainwater in the atmosphere it forms sulfurous acid.SO2 + H2O àH2SO3
c. When sulphur trioxide reacts with rainwater in the atmosphere it forms sulphuric acid.SO3 + H2O à H2SO4
15. What is atmosphere?Ans: The envelope of air that surrounds the earth is called atmosphere.
16. What is troposphere?
Ans: The lowermost layer of atmosphere near the surface of the earth is called troposphere.
17. What is stratosphere?
Ans: The layer of atmosphere which lies just above the troposphere is called the stratosphere.
18. What is mesosphere?
Ans: The layer of atmosphere which lies just above the stratosphere is called mesosphere.
19. What is thermosphere?
Ans: The layer of atmosphere which starts from mesosphere and ends at exosphere is called thermosphere.
20. What is exosphere?
Ans: The outermost layer of the atmosphere is called exosphere.
21. What is ozone?
Ans: Ozone is the molecule of three oxygen atoms which forms ozone-layer in the upper part of the stratosphere.
22. What is green house effect?
Ans: Greenhouse effect is the warming of the earth’s surface that occurs due to the trapping of the sun’s heat by the earth’s atmosphere.
23. What are industrial gases?
Ans: The different gases like sulphur dioxide, carbon dioxide, nitrous oxide, etc. which are produced by industries are called industrial gases.
24. Define chlorofluorocarbon.
Ans: Chlorofluorocarbon is a chemical compound containing carbon, hydrogen, chlorine and fluorine.
25. Define ozone hole.
Ans: An ozone hole is the region of space in the stratosphere where the amount of ozone content has been reduced drastically.
26. Define tropopause.
Ans: The upper boundary of the troposphere is called tropopause.
27. Define mesopause.
Ans: The uppermost layer of the mesosphere is called mesopause.
28. Define stratopause.
Ans: The upper boundary of stratosphere is called stratopause.
29. What is a green house?
Ans: Greenhouse is a building made up of green glasses which can trap the solar radiation in it.
30. Define ozone depletion.
Ans: The loss or damage of ozone in the atmosphere is called ozone depletion.
31. What do you mean by greenhouse gases?
Ans: The gases which are responsible for greenhouse effect are called greenhouse gases.
32. How is the amount of the ozone molecules being balanced naturally?
Ans: Ozone is created primarily in the stratosphere by ultraviolet radiation. When high-energy ultraviolet rays strike on ordinary molecules, they split the molecules into two single oxygen atoms, known as atomic oxygen. A freed oxygen atom then combines with another oxygen molecule to form a molecule of ozone. In this way the amount of the ozone molecules is balanced naturally.
33. Write any three importance of ozone layer?
Ans: The importance of the ozone layer are:
a. It absorbs 99% of ultraviolet rays and prevents them from entering into earth surface.
b. It helps to maintain a suitable temperature of the earth.
c. It protects us from the diseases like blindness, skin cancer, etc.
34. Write any three effects seen in human health due to the depletion of ozone layer.
Ans: The effects seen in human health due to the depletion of ozone layer are:
a. It may cause skin inflammation.
b. Different types of cancers, cataract, loss of immunity, etc. are caused due to it.
c. It also may affect DNA which may cause mutation.
35. Describe in short about the causes of depletion of ozone layer.
Ans: The depletion of ozone layer is the formation of a hole in it or gradual thinning of this layer. Depletion of the ozone layer is caused due to the entry of chemicals like chlorofluorocarbon (CFCs), methyl chloroform, carbon tetrachloride, etc. into the atmosphere. CFCs are the non-toxic, non-inflammable and cheap chemicals used as refrigerant When CFCs are reached into the atmosphere they deplete the ozone layer. In the presence of UV rays, CF2Cl2 splits into ClO and O2. ClO breaks into Cl and O by the UV rays. The Cl and O participate in a chain reaction and cause ozone layer depletion.
36. Write any three characteristics of chlorofluorocarbon.
Ans: The characteristics of chlorofluorocarbon are:
a. Chlorofluorocarbons are non-toxic, non-flammable chemicals.
b. They are used in the manufacturing of aerosols, blowing agents for foams and packing materials, as solvents, and as refrigerants.
c. They are responsible for ozone layer depletion.
37. Write down any three features of troposphere.
Ans: The features of the troposphere are:
a. It extends from 8-10 km at the poles and up to 16 km at the equatorial.
b. It contains oxygen, nitrogen, carbon dioxide, water vapour and dust particles.
c. It is highly affected by human activities.
38. Write any three effects of the increasing quantity of carbon dioxide gas in atmosphere.
Ans: The effects of increasing quantity of carbon dioxide gas in the atmosphere are:
i. The temperature of the earth will increase.
ii. More water vapour evaporates into the atmosphere which increases greenhouse heating.
iii. The carbon dioxide that dissolves in the ocean through direct chemical exchange creates carbonic acid which increases the acidity of the water.
39. Write short notes on:
a. Stratosphere
b. Mesosphere
Ans: a. Stratosphere b. Mesosphere
The layer of atmosphere above the troposphere is called the stratosphere. It is extended up to 16 km to 50 km above the earth’s surface. This region is also called ozonosphere. The ozone layer protects us from the harmful effects of ultraviolet rays of the sun.
b. Mesosphere
The layer of atmosphere above the stratosphere is called mesosphere. It is extended up to 50 km to 80 km above the earth’s surface. It consists of nitrogen, nascent oxygen and oxygen. This layer is the coldest layer of the atmosphere. It has strong wind which blows eastward in the winter and westward in the summer.
40. Write in brief about the climate change policy, 2067.
Ans: Global warming is the result of climate change. It adversely affects human health, agriculture, forest and various human-related aspects. In this regard, the climate change policy has been formulated to create awareness among the people and develop adaption.
40. Draw a labeled diagram of different layers of earth’s atmosphere.
Ans:
SEE Science: History Of Earth
1. What are fossils?
Ans: Fossils are the impressions or remains of animals and plants preserved in the rocks over a million years ago.
2. What is anthracite?
Ans: Anthracite is the hardest coal having highest amount of carbon.
3. When did the evolution of development of fish take place?
Ans: The evolution and development of fish took place in the period of Silurian of Paleozoic era.
4. How is the information about the ancient living beings taken?
Ans: The information about the ancient living beings is taken from their fossils found in sedimentary rocks or hard parts of soil.
5. Write any three information obtained by the study of fossil.
Ans: The following information is obtained by the study of fossil:
a. It provides the information about the structure of the animals and the plants.
b. The condition of a fossil indicates the type of the environment existed at the time.
c. Similar fossils in different areas indicate the patterns in the movement of the earth’s crust.
6. Mention any three importance of fossil.
Ans: The importance of the fossil is given below:
a. They provide evidence of the evolution of living beings.
b. They help to know about the extinct animals and plants.
c. They help to make geological timescale.
7. Write any three ways of identification of fossil.
Ans: The ways of identification of fossil are given below:
a. Traces of dead bodies are formed on sedimentary rocks which can be identified as fossils.
b. A part of the skeletal system or the whole skeleton preserved in sedimentary rocks is a fossil.
c. They are also identified by tallying the fossils with the photos of fossils that were already identified.
8. Describe the process of formation of fossil.
Ans: Fossils are formed in different ways. Most of the fossils are formed when plants or animals die in or near water and is buried in mud, dirt, gravel and hard rock. Soft tissues quickly decompose leaving the hard bones or shells. These hard bones or shells are preserved in their original form in the rock. Some fossils are formed when animals are frozen in ice and preserved to the core. Organisms are also fossilized in the form of casts in sediments. The fossils are exposed at the surface by geographical activities like faulting and surface erosion.
9. What is mineral oil?
Ans: Mineral oil is a liquid mixture of hydrocarbons obtained from petroleum.
10. Write any three importance of mineral oil.
Ans: The importance of mineral oil are:
a. It is used as a lubricant.
b. It is used as fuel for cooking food.
c. It is used in the manufacturing of plastics, chemical fertilizers, pesticides, paints, explosives, medicines, etc.
11. Describe the process of formation of mineral oil.
Ans: Mineral oils are formed by the remains of phytoplankton and zooplankton that are buried under the ocean bed by natural disasters such as earthquakes and volcanic eruption. The drastic change in climate, huge volcanic eruption and massive earthquakes cause micro-organisms of the ocean to get buried under the earth crust where they are compressed under high temperature and pressure in the absence of oxygen. They finally formed mineral oil after the millions of years.
12. What are the two conditions required to form mineral oil inside the earth crust?
Ans: The following conditions are required to form mineral oil:
a. Mineral oils are formed by the remains of phytoplankton and zooplankton that are buried under the ocean bed by natural disasters such as earthquakes and volcanic eruption.
b. When micro-organisms are buried under the earth crust and compressed under high temperature and pressure in the absence of oxygen.
13. What is geological era?
Ans: A very long duration of time which helps to study the geological history of the earth is called a geological era.
14. What are the three periods of the Mesozoic era?
Ans: The three periods of the Mesozoic era are Triassic, Jurassic and Cretaceous.
15. When did the evolution of insects with wings take place?
Ans: The evolution of insects with wings took place in Devonian of Paleozoic era.
16. Define Mesozoic era.
Ans: Mesozoic era is the geological division from 250 million years ago to 65.5 million years ago.
17. Define Cenozoic era.
Ans: Cenozoic era is the geological division from 65.5 million years ago to recent.
18. Which era is called the era of creepers and why?
Ans: Mesozoic era is called the era of creepers because different types of creeping animals like dinosaurs, reptiles, tortoise, etc. were evolved and developed in this era.
19. Why did the life evolve after a long time from the birth of the earth?
Ans: The life evolves after a long time from the birth of the earth because the earth was very hot at the time of its birth and the condition of the environment was not suitable for the evolution of life.
20. Write any three events which occurred in the mesozoic era.
Ans: The important events which occurred in mesozoic era are:
a. The giant reptiles like dinosaurs evolved, flourished and were extinct.
b. Climate became suitable for aquatic, terrestrial and aerial animals.
c. Mammals and birds began to evolve at the end of this era.
21. Write down the duration of Paleozoic era and enlist the major events of this era.
Ans: Paleozoic era began about 570 million years ago and ended about 250 million years ago.
The major events of this era are:
a. Sedimentary rocks were formed.
b. Aquatic and terrestrial vertebrates and invertebrates were evolved.
c. Climatic change and change in atmosphere took place.
22. Mention the major events in Mesozoic era regarding evolution of living beings.
Ans: The major events in mesozoic era regarding evolution of living beings are:
a. Mammals and birds began to evolve at the end of this era.
b. Flowering plants were developed.
c. The giant reptiles like dinosaurs evolved, flourished and were extinct.
23. Write the name of era and its duration for each of the following incidents.
Era: Proterozoic era
Duration: 2500 -542 million years ago
b. Evolution of human beings
Era: Cenozoic
Duration: 65 million years ago to till now
c. Evolution and extinction of the dinosaur
Evolution of dinosaur: the Mesozoic era
Extinction of dinosaur: Mesozoic era
Duration: 252-65 million years ago
24. Write down the duration of mesozoic era and describe the origin of organisms in this era.
Ans: The Mesozoic era began about 250 million years ago and ended 65 million years ago. Mammals and birds began to evolve at the end of this era. The giant reptiles like dinosaurs evolved, flourished and were extinct. Turtles, crocodile-like species and frogs made their first appearances in this era. Flowering plants were developed. Coniferous plants were developed. Gymnosperms were dominating plants of this era.
25. Mention the duration of paleozoic era. Explain about the origin of organisms in paleozoic era.
Ans: The Palaeozoic era began 570 million years ago and ended about 250 million years ago. Aquatic and terrestrial vertebrates and invertebrates evolved in this era. The first vertebrate appeared in the form of primitive fish, some fish had lungs and powerful bony fins. The bones in their fins eventually evolved into legs and became the first tetrapods. Macroscopic plant life appeared in the early Palaeozoic era.
Different bryophytes and pteridophytes were evolved.
Fern plant up to 25 ft and club moss up to 100 ft were evolved in this era.
26. Write down the duration of cenozoic era. Describe in brief about the origin of organisms in cenozoic era.
Ans: Cenozoic era began 65 years ago and still going on. The first primates and horses were evolved in this era. Mammals, birds and insects were spread. Rhinoceros, camels, elephants, first modern mammals were evolved during this era. Angiosperm spread rapidly. This era is also known as the era of human beings. Earliest man, a man in Stone age and human cultures were developed during this era.
27. Write short notes on:
Pre Cambrian era started about 4.6 billion years ago and ended 570 million years ago. It is the combination of the archeozoic, Proterozoic and Cenozoic era. The early part of this era is the beginning of the earth. Formation of atmosphere, hydrosphere and lithosphere took place. Unicellular and multicellular organisms were evolved in a shallow sea. Very primitive bacteria were evolved during this era.
b. Mesozoic era
The Mesozoic era began about 250 million years ago and ended 65 million years ago. Mammals and birds began to evolve at the end of this era. The giant reptiles like dinosaurs evolved, flourished and were extinct. Turtles, crocodile-like species and frogs made their first appearances in this era. Flowering plants were developed. Coniferous plants were developed. Gymnosperms were dominating plants of this era. Hill and mountains were formed. The climate became suitable for aquatic, terrestrial and aerial life.
28. What is earth science?
Ans: Earth science is the study of nature, distribution, behaviour and origin of the materials of the earth and its atmosphere.
29. What is geology?
Ans: The study of earth science is known as geology.
30. State Nubular theory.
Ans: The nebular theory states that the whole of our solar system was formed from a very big mass of the dust and gases called nebula which was whirling on its own axis.
31. How is it known that there were dinosaurs on the earth in the ancient time? In which era were they dominant? What is the time duration of that era?
Ans: It is known that there were dinosaurs on the earth in the ancient time by the study of fossils.
They were dominant in the Mesozoic era.
The Mesozoic era began about 250 million years ago and ended about 65 million years ago.
32. Write short notes on:
According to Nebular hypothesis, the sun and the planets were formed from a large whirling cloud of hot gases and dust. When the cloud cooled and grew smaller, it began to spin faster. As the surface of the cloud cooled by radiation, a ring of matter was formed at the equatorial region of it. The ring escaped out from the surface of the main mass and the first planet was formed. The process was repeated till the entire solar system was formed. The remaining mass formed the sun.
b. Tidal hypothesis
According to this hypothesis, the sun was a very big and extensive mass of gas which was moving in space. A big comet came closer to the sun and gravitational force of the comet attracted the sun, then the molten mass of the sun was elongated toward the comet forming tides. As the star moved away from the sun, some parts of the tide broke down into number of pieces, which became planet and satellite. Finally they began to revolve around the sun.
33. What is carbon dating?
Ans: The process of recognizing the age of the organism is called carbon dating.
34. What is coal?
Ans: Coal is a fossil fuel which is obtained from plants buried under the earth as thick layers, millions of years ago.
35. What is refining?
Ans: The process of purifying crude oil is known as refining.
36. What are fossil fuels?
Ans: Fossil fuels are the buried combustible geologic deposits of organic materials, formed from decayed plants and animals after millions of years.
37. How is coal formed?
Ans: Coal is formed by the decomposition of large plants and trees buried under the earth crust for millions of years.
38. Describe the method of coal formation.
Ans: Coal is formed when the remains of trees, fern and other plants are buried under the soil by a natural disaster such as earthquakes and volcanic eruptions. As more soil deposited on them, they are compressed. When the temperature rises they sink deeper. As the process continues, they are protected from biodegradation and oxidation. This trapped carbon slowly converts into coal under high pressure and temperature in the absence of oxygen.
Ans: Fossils are the impressions or remains of animals and plants preserved in the rocks over a million years ago.
2. What is anthracite?
Ans: Anthracite is the hardest coal having highest amount of carbon.
3. When did the evolution of development of fish take place?
Ans: The evolution and development of fish took place in the period of Silurian of Paleozoic era.
4. How is the information about the ancient living beings taken?
Ans: The information about the ancient living beings is taken from their fossils found in sedimentary rocks or hard parts of soil.
5. Write any three information obtained by the study of fossil.
Ans: The following information is obtained by the study of fossil:
a. It provides the information about the structure of the animals and the plants.
b. The condition of a fossil indicates the type of the environment existed at the time.
c. Similar fossils in different areas indicate the patterns in the movement of the earth’s crust.
6. Mention any three importance of fossil.
Ans: The importance of the fossil is given below:
a. They provide evidence of the evolution of living beings.
b. They help to know about the extinct animals and plants.
c. They help to make geological timescale.
7. Write any three ways of identification of fossil.
Ans: The ways of identification of fossil are given below:
a. Traces of dead bodies are formed on sedimentary rocks which can be identified as fossils.
b. A part of the skeletal system or the whole skeleton preserved in sedimentary rocks is a fossil.
c. They are also identified by tallying the fossils with the photos of fossils that were already identified.
8. Describe the process of formation of fossil.
Ans: Fossils are formed in different ways. Most of the fossils are formed when plants or animals die in or near water and is buried in mud, dirt, gravel and hard rock. Soft tissues quickly decompose leaving the hard bones or shells. These hard bones or shells are preserved in their original form in the rock. Some fossils are formed when animals are frozen in ice and preserved to the core. Organisms are also fossilized in the form of casts in sediments. The fossils are exposed at the surface by geographical activities like faulting and surface erosion.
9. What is mineral oil?
Ans: Mineral oil is a liquid mixture of hydrocarbons obtained from petroleum.
10. Write any three importance of mineral oil.
Ans: The importance of mineral oil are:
a. It is used as a lubricant.
b. It is used as fuel for cooking food.
c. It is used in the manufacturing of plastics, chemical fertilizers, pesticides, paints, explosives, medicines, etc.
11. Describe the process of formation of mineral oil.
Ans: Mineral oils are formed by the remains of phytoplankton and zooplankton that are buried under the ocean bed by natural disasters such as earthquakes and volcanic eruption. The drastic change in climate, huge volcanic eruption and massive earthquakes cause micro-organisms of the ocean to get buried under the earth crust where they are compressed under high temperature and pressure in the absence of oxygen. They finally formed mineral oil after the millions of years.
12. What are the two conditions required to form mineral oil inside the earth crust?
Ans: The following conditions are required to form mineral oil:
a. Mineral oils are formed by the remains of phytoplankton and zooplankton that are buried under the ocean bed by natural disasters such as earthquakes and volcanic eruption.
b. When micro-organisms are buried under the earth crust and compressed under high temperature and pressure in the absence of oxygen.
13. What is geological era?
Ans: A very long duration of time which helps to study the geological history of the earth is called a geological era.
14. What are the three periods of the Mesozoic era?
Ans: The three periods of the Mesozoic era are Triassic, Jurassic and Cretaceous.
15. When did the evolution of insects with wings take place?
Ans: The evolution of insects with wings took place in Devonian of Paleozoic era.
16. Define Mesozoic era.
Ans: Mesozoic era is the geological division from 250 million years ago to 65.5 million years ago.
17. Define Cenozoic era.
Ans: Cenozoic era is the geological division from 65.5 million years ago to recent.
18. Which era is called the era of creepers and why?
Ans: Mesozoic era is called the era of creepers because different types of creeping animals like dinosaurs, reptiles, tortoise, etc. were evolved and developed in this era.
19. Why did the life evolve after a long time from the birth of the earth?
Ans: The life evolves after a long time from the birth of the earth because the earth was very hot at the time of its birth and the condition of the environment was not suitable for the evolution of life.
20. Write any three events which occurred in the mesozoic era.
Ans: The important events which occurred in mesozoic era are:
a. The giant reptiles like dinosaurs evolved, flourished and were extinct.
b. Climate became suitable for aquatic, terrestrial and aerial animals.
c. Mammals and birds began to evolve at the end of this era.
21. Write down the duration of Paleozoic era and enlist the major events of this era.
Ans: Paleozoic era began about 570 million years ago and ended about 250 million years ago.
The major events of this era are:
a. Sedimentary rocks were formed.
b. Aquatic and terrestrial vertebrates and invertebrates were evolved.
c. Climatic change and change in atmosphere took place.
22. Mention the major events in Mesozoic era regarding evolution of living beings.
Ans: The major events in mesozoic era regarding evolution of living beings are:
a. Mammals and birds began to evolve at the end of this era.
b. Flowering plants were developed.
c. The giant reptiles like dinosaurs evolved, flourished and were extinct.
23. Write the name of era and its duration for each of the following incidents.
a. Invertebrates originated in sea
b. Evolution of human beings
c. Evolution and extinction of dinosaurs
Ans: a. Invertebrates originated in seab. Evolution of human beings
c. Evolution and extinction of dinosaurs
Era: Proterozoic era
Duration: 2500 -542 million years ago
b. Evolution of human beings
Era: Cenozoic
Duration: 65 million years ago to till now
c. Evolution and extinction of the dinosaur
Evolution of dinosaur: the Mesozoic era
Extinction of dinosaur: Mesozoic era
Duration: 252-65 million years ago
24. Write down the duration of mesozoic era and describe the origin of organisms in this era.
Ans: The Mesozoic era began about 250 million years ago and ended 65 million years ago. Mammals and birds began to evolve at the end of this era. The giant reptiles like dinosaurs evolved, flourished and were extinct. Turtles, crocodile-like species and frogs made their first appearances in this era. Flowering plants were developed. Coniferous plants were developed. Gymnosperms were dominating plants of this era.
25. Mention the duration of paleozoic era. Explain about the origin of organisms in paleozoic era.
Ans: The Palaeozoic era began 570 million years ago and ended about 250 million years ago. Aquatic and terrestrial vertebrates and invertebrates evolved in this era. The first vertebrate appeared in the form of primitive fish, some fish had lungs and powerful bony fins. The bones in their fins eventually evolved into legs and became the first tetrapods. Macroscopic plant life appeared in the early Palaeozoic era.
Different bryophytes and pteridophytes were evolved.
Fern plant up to 25 ft and club moss up to 100 ft were evolved in this era.
26. Write down the duration of cenozoic era. Describe in brief about the origin of organisms in cenozoic era.
Ans: Cenozoic era began 65 years ago and still going on. The first primates and horses were evolved in this era. Mammals, birds and insects were spread. Rhinoceros, camels, elephants, first modern mammals were evolved during this era. Angiosperm spread rapidly. This era is also known as the era of human beings. Earliest man, a man in Stone age and human cultures were developed during this era.
27. Write short notes on:
a. Pre Cambrian era
b. Mesozoic era
Ans: a. Pre Cambrian erab. Mesozoic era
Pre Cambrian era started about 4.6 billion years ago and ended 570 million years ago. It is the combination of the archeozoic, Proterozoic and Cenozoic era. The early part of this era is the beginning of the earth. Formation of atmosphere, hydrosphere and lithosphere took place. Unicellular and multicellular organisms were evolved in a shallow sea. Very primitive bacteria were evolved during this era.
b. Mesozoic era
The Mesozoic era began about 250 million years ago and ended 65 million years ago. Mammals and birds began to evolve at the end of this era. The giant reptiles like dinosaurs evolved, flourished and were extinct. Turtles, crocodile-like species and frogs made their first appearances in this era. Flowering plants were developed. Coniferous plants were developed. Gymnosperms were dominating plants of this era. Hill and mountains were formed. The climate became suitable for aquatic, terrestrial and aerial life.
28. What is earth science?
Ans: Earth science is the study of nature, distribution, behaviour and origin of the materials of the earth and its atmosphere.
29. What is geology?
Ans: The study of earth science is known as geology.
30. State Nubular theory.
Ans: The nebular theory states that the whole of our solar system was formed from a very big mass of the dust and gases called nebula which was whirling on its own axis.
31. How is it known that there were dinosaurs on the earth in the ancient time? In which era were they dominant? What is the time duration of that era?
Ans: It is known that there were dinosaurs on the earth in the ancient time by the study of fossils.
They were dominant in the Mesozoic era.
The Mesozoic era began about 250 million years ago and ended about 65 million years ago.
32. Write short notes on:
a. Nebular hypothesis
b. Tidal hypothesis
Ans: a. Nebular hypothesisb. Tidal hypothesis
According to Nebular hypothesis, the sun and the planets were formed from a large whirling cloud of hot gases and dust. When the cloud cooled and grew smaller, it began to spin faster. As the surface of the cloud cooled by radiation, a ring of matter was formed at the equatorial region of it. The ring escaped out from the surface of the main mass and the first planet was formed. The process was repeated till the entire solar system was formed. The remaining mass formed the sun.
b. Tidal hypothesis
According to this hypothesis, the sun was a very big and extensive mass of gas which was moving in space. A big comet came closer to the sun and gravitational force of the comet attracted the sun, then the molten mass of the sun was elongated toward the comet forming tides. As the star moved away from the sun, some parts of the tide broke down into number of pieces, which became planet and satellite. Finally they began to revolve around the sun.
33. What is carbon dating?
Ans: The process of recognizing the age of the organism is called carbon dating.
34. What is coal?
Ans: Coal is a fossil fuel which is obtained from plants buried under the earth as thick layers, millions of years ago.
35. What is refining?
Ans: The process of purifying crude oil is known as refining.
36. What are fossil fuels?
Ans: Fossil fuels are the buried combustible geologic deposits of organic materials, formed from decayed plants and animals after millions of years.
37. How is coal formed?
Ans: Coal is formed by the decomposition of large plants and trees buried under the earth crust for millions of years.
38. Describe the method of coal formation.
Ans: Coal is formed when the remains of trees, fern and other plants are buried under the soil by a natural disaster such as earthquakes and volcanic eruptions. As more soil deposited on them, they are compressed. When the temperature rises they sink deeper. As the process continues, they are protected from biodegradation and oxidation. This trapped carbon slowly converts into coal under high pressure and temperature in the absence of oxygen.
Wednesday, January 2, 2019
SEE Science: Model Questions 2074 Set 2
Full Marks: 75
answer according to the given instructions.
Group - A
a. Write any two factors one which gravitational force depend.
Answer:
क. कुनै दुई वस्तुहरुको पिण्ड।
ख. वस्तुहरुको केन्द्र सम्म वीचको दूरीमा।
b. Write the value of atmospheric pressure at sea level.
Answer:
c. Give any two examples of radioactive elements.
Answer:
क. युरेनियम।
ख. प्लुटोनियम।
d. Write its SI unit of power of lens.
Answer:
डायोप्टर (D)
e. What is heating element?
Answer: ताप उपकरणहरुमा विधुत शक्तिलाई तापक्रम रुपान्तर गर्न प्रयोग गरिने तारलाई हिटिङ्ग इलेमेन्ट भनिन्छ।
f. State Mendeleev's periodic law.
Answer: तथ्यहरुका भौतिक र रासायनिक गुणहरु तिनीहरुका परमाणविक भारहरुका पेरियोडीक कार्य स्वरूप हुन्छन्।"
g. Give two examples of organic acid.
Answer:
क. साइट्रिक एसिड।
ख. एसेटिक एसिड।
h. Write the atomic number and atomic mass of aluminium.
Answer:
क. परमाणविक संख्या - 13.
ख. परमाणविक भार - 27.
i What is saponification?
Answer: वनस्पति वा जनावरको बोसोलाई अल्काली संग प्रतिक्रिया गराएर साबुन उत्पादन गर्ने प्रक्रियालाई सेपोनीफिकेसन भनिन्छ।
j. Name two types of silkworm cultivated in Nepal.
Answer:
क. सेरी रेसम कीरा।
ख. एरी रेसम कीरा।
k. What are the two parts of central nervous system?
Answer:
क. मस्तिष्क (Brain).
ख. सुषुम्ना (Spinal Cord).
l. Write an organ that produces uric acid in a human body.
Answer: मृगौला (Kidney)
m. What is gene?
Answer: जीवहरुको अनुवंशिक गुण एक वंशबाट अर्को वंशमा सार्ने क्रोमोजोम भित्र रहेका तत्वलाई वंशाणु भनिन्छ।
n. Which parts of a flower change into seed and fruit after fertilization?
Answer:
क. ओभ्यूल - बीउ।
ख. ओभरी - फल।
o. What is geological time scale?
Answer: एउटा समय तालिका जसले पृथ्वीको इतिहासको उत्पति देखि वर्तमान समय सम्म पूरा गर्दछ त्यसलाई भौगोलिक समय तालिका भनिन्छ।
Group 'B' [13× 2 = 26]
Answer:
गुरुत्वबल | गुरुत्वप्रवेग |
| a. कुनै पनि वस्तुलाई पृथ्वीले आफ्नो केन्द्रतिर आकर्षण गर्ने बल भनेको गुरुत्वबल हो। | a. पृथ्वीको सतहतिर स्वतन्त्र रुपले खसिरहेको वस्तुमा गुरुत्व बलले गर्दा उत्पन्न हुने प्रवेग भनेको गुरुत्वप्रवेग हो। |
| b. यो कारण हो। | b. यो असर हो। |
3. Why is it easier to pull a bucket of water from the well until it is inside the water but difficult when it is out of water?
Answer: पानीभित्र बाल्टी भइन्जेल पानीले दिने उर्ध्वचाप बाल्टिनमा लाग्दछ। पानीले दिने उर्ध्वचापले गर्दा बाल्टिन उठाउन कम बलको आवश्यकता पर्दछ र बाल्टिन उचाल्न सजिलो हुन्छ। पानी बाहिर हावाको उर्ध्वचाप नगन्य हुन्छ जसले गर्दा बाल्टिन उचाल्न पुरै तौल थाम्नु पर्ने हुन्छ, त्यसैले उचाल्न गह्रौं हुन्छ।
4. It is given jerk before being used to measure temperature again of a clinical thermometer, why?
Answer: क्लिनिकल थर्मोमिटरको केश नलीमा बल्बतिर साँघुरो घाँटी बनाइएको हुन्छ। थर्मोमिटरलाई विरामीको काखी वा जीब्रोमुनि राख्दा तापक्रमको बृद्दीले गर्दा पारो सजिलै संग थर्मोमिटरको नालीमा चढ्छ तर तापक्रम घट्दा चढेको पारो बल्बमा आफ्सेआफ फर्केर आउँदैन जसले अर्को विरामीको तापक्रम मापन गर्न सकिदैन त्यसैले परोलाई पुन: बल्बमा फर्काउन धेरै ठुलो झड्का दिनु पर्दछ।
5. Why is the inner wall of a fluorescent lamp coated with fluorescent powder?
Answer: जब फ्लोरेसेण्ट बत्तीको मर्करी परमाणुहरुले इलेक्ट्रोनहरुको हिर्काईमा अल्ट्राभ्वाइलेट किरणहरु फाल्दछन्, ती किरणहरु फ्लोरेसेण्ट पाउडरमा पर्दछन्। यसरी अल्ट्राभ्वाइलेट किरणहरु उक्त फ्लोरेसेण्ट पर्दा देख्न सकिने किरण (Visible Light) मा परिणत गर्दछ।
6. Why are elements of group VII called halogens?
Answer: ग्रुप VII A का तत्वहरुले धातुसँग प्रतिक्रिया गरी लवन (Salt) बनाउँदछन्। त्यसैले ग्रुप VII A तत्वहरुलाई हेलोजन्स् भनिन्छ।
7. Write a chemical reaction which is carried out by catalyst with balanced equation.
Answer:
8. Solution of ammonia is a weak alkali, why?
Answer: एमोनियम हाईड्रोअक्साइड पानीमा घोल्दा थोरै मात्रामा हाईड्रोअक्साइड (OH−)आयोनहरु दिन्छ। त्यसैले एमोनियम हाईड्रोअक्साइड एउटा कम्जोर अल्काली हो।
9. Write two importance of glucose in human body.
Answer:
क. यो मानव शरीरमा शक्तिको श्रोत हो।
ख. यसले मानव शरीरमा मेटाबोलिज्मको सन्तुलनमा महत्वपूर्ण कार्य गर्दछ।
10. Why silkworm is called queen of fibre?
Answer: रेशम किराबाट निस्कने रेशा धेरै लामो, टल्किने, तन्किन सक्ने र पानी कम सोस्ने भएकोले यसलाई धागोहरुको रानी भनिन्छ।
11. Write any two differences between sensory nerve and motor nerve.
Answer:
Sensory Nerve | Motor Nerve |
| a. यसले चेतना ज्ञानेन्द्रीयबाट मस्तिष्कसम्म पुर्याउँछ। | a. यसले ज्ञान वा प्रेरणा मस्तिष्कबाट ज्ञानेन्द्रीयसम्म पुर्याउँछ। |
| b. यी स्नायुहरु थोरै छन्। | b. यी स्नायुहरु धेरै छन्। |
12. Write any two characteristics of a person suffering from downs syndrome.
Answer:
क. छोटो कद सहितको सानो र गोलो टाउको हुन्छ।
ख. चिरा परेको जिब्रो र आधा खुलेको मुख हुन्छ।
13. Write two importance of variation.
Answer:
क. यसले गर्दा क्रम विकाशका साथै नयाँ जीवहरुको उत्पत्ती हुन्छ।
ख. यसले जीवहरुलाई परिवर्तित वातावरणमा अनुकुलता प्रदान गर्दछ।
14. A comet is not actually a star. Give two reasons in favour of this statement.
Answer:
क. पुच्छ्रे ताराको आफ्नै प्रकाश छैन यो सूर्यको प्रकाशले गर्दा नजिक आउँदा चम्किलो देखिन्छ।
ख. पुच्छ्रे ताराले सूर्यलाई लम्बिएको अन्डाकार कक्षमा परिक्रमा गर्छ।
Group 'C' [6×3 = 18]
ख. उल्टो/वस्तु भन्दा सानो।
यो फोटो ग्राफिक क्यामेरामा प्रयोग गरिन्छ।
16. Draw a diagram of a step up transformer and mention its any two parts.
Answer:
17. How will you manufacture of ammonia gas on industrial scale ? Write with balanced chemical equation.
Answer: एमोनिया ग्याँसलाई औधोगिक रुपमा उत्पादन गर्नु 1 भाग नाइट्रोजन र 3 भाग हाईड्रोजनलाई 500°C तापक्रम र 250 Atm चापमा फलामको धुलोलाई उत्प्रेरक र मलिब्डेनम लाई प्रोमोटर को रुपमा प्रयोग गरी रासायनिक प्रतिक्रिया गराई उत्पादन गरिन्छ।
18. How is compost fertilizer made? Explain.
Answer: कम्पोष्ट मल बनाउनका लागि कुहिन योग्य अनावश्यक ठोस वस्तुहरु जस्तै बोट विरुवाका पातहरु कृषिजन्य उपजहरु, फलफूलका बोक्राहरु, सागसब्जी केलाउँदा प्राप्त हुने पातपतिङ्गरहरु, बासी खानेकुराहरु र गाई भैंसी र वस्तुभाउका मलमुत्रहरु प्रयोग गरिन्छ। कम्पोष्ट मल बनाउन माथि उल्लेखित वस्तुहरुलाई 5 m लामो 1.5 m चौडाई र 1.5 m गहिरो खाल्डो खनी त्यसमा उक्त वस्तुहरुलाई चिसो माटोले छोप्नु पर्छ। यसरी उक्त वस्तुहरु तह तह राखी 3-4 महिना छोड्नु पर्दछ। माटोमा भएका व्याक्टेरिया र फन्जाईले उक्त वस्तुहरुलाई कुहाउँदछन् र 3-4 महिना पछि कम्पोष्ट मल तयार हुन्छ।
19. Pea plants with red flower (RR) and white flower (rr) are cross pollinated first then self pollinated. What will be the colour of flower in first and second generation of that pea plant and why? Write with necessary chart of filial generation.
Answer:
20. How does air pollution inhibit biological growth of plants? Explain.
Answer:" state="close"]वायु मण्डल प्रदूषित हुँदा सौर्य प्रकाशको तीव्रतामा ह्रास आउँछ। यसरी सौर्य प्रकाशको तीव्रतामा कमी हुँदा विरुवाका पातहरुमा रहेका सानासाना छिद्रहरु (Stomata) राम्ररी खुल्न पाउँदैन। जसले गर्दा पातभित्र प्रशस्त मात्रामा कार्बनडाईअकसाईड (Carbondioxide) ग्याँस जान पाउँदैन र प्रकाश संश्लेषण प्रक्रियामा गतिरोध खडा हुन्छ। विरुवाले खाना बनाउन सक्दैन जसको परिणाम स्वरुप विरुवाको भौतिक गतिविधि र विकासमा वाधा पुग्छ।
Group 'D' [4×4 = 16]
Answer: पानि तान्ने पम्पमा दुई भाग हुन्छ, जसलाई ब्यारेल र पिस्टन भनिन्छ। ब्यारेल र पिस्टन दुवैमा एउटा एउटा भल्भ हुन्छन्। एउटा भल्भ पिस्टनमा हुन्छ भने अर्को भल्भ V2 ब्यारेलको पिँधमा हुन्छ। दुवै भल्भहरुले सानो ढोकाको काम गर्दछन्। यसले पानीलाई माथि आउन दिन्छ, तर तल फर्किन दिँदैन पानी तान्दा निम्न दुई क्रियाहरु हुन्छन् जसलाई क्रमश अप स्ट्रोक र डाउन स्ट्रोक भनिन्छ।
अप स्ट्रोक: पम्पको ह्यान्डललाई तलतिर थिच्दा पिस्टन माथितिर तानिन्छ र भल्भ V1 बन्द हुन्छ। पिस्टन मुनिको ब्यारेलको भागमा चाप कम हुन्छ। जमीन मुनिको पानीको सतहमा क्रियाशील वायुमण्डलीय चापले पानीलाई पाइपको बाटो गरी भल्व V2 लाई माथितिर धकेल्दै ब्यारेल भित्र पुर्याउँदछ।
22. Study the structural formula of the hydrocarbon given below and answer the following questions.
(a) Give the name and molecular formula of this compound.
(b) Write its general formula.
(d) Write a use of the compound thus formed.
Answer:
23. The diagram below represents a certain category of blood vessel showing the role of a special structure in their walls.
(b) What is the structure shown inside the blood vessels?
(c) What is the role of these structures?
(d) Are these structures present in any other kind of blood vessel? If so, name it.
Answer:
a. शिरा।
b. सेमिलुनर भल्भ।
c. यसले रगतलाई एउतै दिशामा बग्न मद्दत गर्दछ र पुन: फर्किनबाट रोक्दछ।
d. हुन्छन्। एओर्टा र पल्मोनरी धमनी।
24. Following are the findings in a study done on the earth environment: The temperature of respective environment is increasing. The number of amphibians is decreasing. Human beings are suffering from cataracts and skin cancer. Answer teh following questions on basis of above facts:
(a) What is the cause of above finding?
(b) What is to be done to remain safe from above conditions?
(c) Write its one more harmful effect to health.
(d) What happens to the environmental temperature at this condition?
Answer:
a. यसको कारक तत्व ओजोन तहको क्षय हो।
b. ओजोन तहलाई सुरक्षीत राख्न CFC, CO, CO2, N2O (नाइट्रस अक्साइड), CH4 आदिको उत्पादनमा रोक लगाउनु पर्छ।
c. यसको कारणले मानिसको स्वास्थ्यमा पर्ने खराब असरहरु रोग निरोधक क्षमत न्यून हुने र श्वास प्रश्वाश प्रणालीमा नकारात्मक असर पर्छ।
d. वातावरणको तापक्रम बृद्दी हुँदै गइरहेको छ।
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