Group (Physics)
1. (a) 1 m long lever is used to lift the load of 600 N by using an effort of 200 N. If load 20 cm far from the fulcrum then calculate mechanical advantage, velocity ratio and efficiency. [3]
Answer
Load (L) = 600 N
Load distance (Ld) = 20 cm =20 = 0.2 m
Effort (E) = 200 N
Effort distance (Ed) = 80 cm = 0.8 m
Mechanical advantage (MA) =?
Velocity ratio (VR) =?
Efficiency (ɳ) =?
We have,
MA = L/(E ) =600 = 3
Again, VR =Ed Ld 0.8 = 4
Finally,
Efficiency =MA VR 3 х 100% = 75%
Hence, MA, VR, and efficiency of the lever is 3, 4 and 75% respectively.
Load distance (Ld) = 20 cm =
Effort (E) = 200 N
Effort distance (Ed) = 80 cm = 0.8 m
Mechanical advantage (MA) =?
Velocity ratio (VR) =?
Efficiency (ɳ) =?
We have,
MA = L/(E ) =
Again, VR =
Finally,
Efficiency =
Hence, MA, VR, and efficiency of the lever is 3, 4 and 75% respectively.
(b) Convert 200oC into oF.
[2]
[2]
Answer
Here,
Given,
C = 200oC
F =?
We have,
100 = 32
Or,200 = 32
F = 328oF
Hence, 200oC is equal 328oF.
Given,
C = 200oC
F =?
We have,
Or,
F = 328oF
Hence, 200oC is equal 328oF.
2. (a) A copper piece cannot be made a magnet. Why? [2]
Answer
A piece of copper is diamagnetic. Diamagnetism is the property of an object which causes it to create a magnetic field in opposition to an externally applied magnetic field, thus causing a repulsive effect. Hence, Copper cannot be made a magnet.
(b) Define fundamental unit. Convert 3500 mm into metre. Define MKS system. [3]
Answer
Fundamental unit -
Those units which are used to express fundamental quantities are called fundamental units. Fundamental units are independent of other units. For example metre, second, etc.
Here,
We have, 1000 mm = 1 m
1 mm =1 m
Or, 3500 mm =3500 m = 3.5 m
3500 mm is equal to 3.5 metre.
MKS system -
The system of units in which length is measured in metre, mass in kilogram and time in second is called MKS system.
Those units which are used to express fundamental quantities are called fundamental units. Fundamental units are independent of other units. For example metre, second, etc.
Here,
We have, 1000 mm = 1 m
1 mm =
Or, 3500 mm =
3500 mm is equal to 3.5 metre.
MKS system -
The system of units in which length is measured in metre, mass in kilogram and time in second is called MKS system.
3. (a) A magnet has more force at poles that at its middle. Why? [2]
Answer
The magnetic force or attraction is greater where the field lines are crowded. Since all the magnetic field lines generate from the poles, the crowd of field lines is maximum near pole.
(b) Write the principal of conservation energy. Write two differences between nuclear fusion and nuclear fission. [3]
Answer
Principle of conservation of energy states that, 'Energy can neither be created nor destroyed, but it can be changed from one from to another.'
Differences between nuclear fusion and nuclear fission are as followings:
Differences between nuclear fusion and nuclear fission are as followings:
| Nuclear fusion | Nuclear fission |
| In nuclear fusion two light nuclei fuse to form one heavy nucleus. | In nuclear fission a heavy nucleus breaks to give two light nuclei. |
| Chain reaction is not involved in nuclear fusion. | It involves a chain reaction. |
4. (a) What is density? A water tank has dimensions of 6 m х 4 m х 4 m. Find the pressure exerted by water at the base of dam when it is filled half. (Density of water = 1000 kg/m3, acceleration due to gravity is 9.8 m/s2) [3]
Answer
Density -
Density is defined as amount of mass contained in unit volume of a body.
Here,
Given,
Density of liquid (d) = 1000 kg/m3
Depth of liquid (h) = 2 m (because base is only half filled)
Acceleration due to gravity (g) = 9.8 m/s2
Pressure (P) =?
We have,
P = hdg
P = 2 х 1000 х 9.8 = 19600 Pa
Hence, the pressure exerted by water at the base of dam is 19600 Pa.
Density is defined as amount of mass contained in unit volume of a body.
Here,
Given,
Density of liquid (d) = 1000 kg/m3
Depth of liquid (h) = 2 m (because base is only half filled)
Acceleration due to gravity (g) = 9.8 m/s2
Pressure (P) =?
We have,
P = hdg
P = 2 х 1000 х 9.8 = 19600 Pa
Hence, the pressure exerted by water at the base of dam is 19600 Pa.
(b) Write short notes on fuse. [3]
Answer
A fuse is a safety device which is made of thin wire with high resistance and a low melting point. It is an alloy of tin and lead and is always connected in the live wire. If current flowing through it is more than the required amount, it gets heated and melts breaking the circuit.
The capacity of the fuse used should be slightly more than the maximum current that flow over it. If a fuse of lower rating than the required is used, it will blow out unnecessarily. If the fuse of much higher rating is used then the appliances becomes unsafe because more electric current flows through it resulting the damage of appliance and also risk of fire in some cases. Thus, the fuse of nearest high value should be used.
The capacity of the fuse used should be slightly more than the maximum current that flow over it. If a fuse of lower rating than the required is used, it will blow out unnecessarily. If the fuse of much higher rating is used then the appliances becomes unsafe because more electric current flows through it resulting the damage of appliance and also risk of fire in some cases. Thus, the fuse of nearest high value should be used.
5. (a) Name any two thermometric liquid that are used in thermometer. Write any two differences between clinical and laboratory thermometer. [3]
Answer
Thermometric liquid used in thermometer are as followings:
• Mercury
• Alcohol
The differences between clinical thermometer and laboratory thermometer are as followings:
• Mercury
• Alcohol
The differences between clinical thermometer and laboratory thermometer are as followings:
| Clinical thermometer | Laboratory thermometer |
| Clinical thermometer is scaled from 35ᵒC to 42ᵒC or from 94ᵒF to 108ᵒF. | Laboratory thermometer is generally scaled from -10ᵒC to 110ᵒC. |
| Clinical thermometer is used to take body temperature. | Laboratory thermometer is used to take the temperature of laboratory. |
(b) Define ferromagnetic, paramagnetic and diamagnetic substances with examples? [3]
Answer
The substances which are strongly attracted by the magnets are known as ferromagnetic substances. For example: iron, cobalt, nickel etc.
The substances that show feeble (weak) attraction towards magnets are called paramagnetic substances. For example: Manganese, platinum and oxygen.
The substances which create a magnetic field in the opposition to an externally applied magnetic field, thus causing them to repel are known as diamagnetic substances. For example: Zinc, Copper, and Mercury.
The substances that show feeble (weak) attraction towards magnets are called paramagnetic substances. For example: Manganese, platinum and oxygen.
The substances which create a magnetic field in the opposition to an externally applied magnetic field, thus causing them to repel are known as diamagnetic substances. For example: Zinc, Copper, and Mercury.
Group (Chemistry)
6. (a) What is fractional distillation? Write its one use. Which method is suitable to obtain pure water from sugar solution? [3]
Answer
The process of separation of mixture of two or more than two miscible liquid components having different boiling points by using a fractionating column is called fractional distillation.
Use of fractional distillation-
Fractional distillation is widely used in industry to purify and separate miscible liquids, alcohol and water, crude petroleum substances and nitrogen from liquid.
Crystallization/evapouration process is suitable to obtain pure water from sugar solution.
Use of fractional distillation-
Fractional distillation is widely used in industry to purify and separate miscible liquids, alcohol and water, crude petroleum substances and nitrogen from liquid.
Crystallization/evapouration process is suitable to obtain pure water from sugar solution.
(b) What are the subatomic particles? What does 2n2 rule indicate? [2]
Answer
Atoms are made up of three fundamental particles: electron, proton and neutron. These are called subatomic particles.
2n2 rule indicates maximum number of electrons in different shell (K, L, M, N.....) of an atom.
2n2 rule indicates maximum number of electrons in different shell (K, L, M, N.....) of an atom.
7. (a) What is mixture? Write its types. [2]
Answer
A mixture is a matter containing two or more substances in any proportion by mass which retains the properties of its constituents.
Types of mixture
i. Homogeneous mixture
ii. Heterogeneous mixture
Types of mixture
i. Homogeneous mixture
ii. Heterogeneous mixture
(b) Why gold is called metal? Give any two reasons. [2]
Answer
Gold is called metal due to following reasons:
i. They possess metallic lustre.
ii. They have high melting and boiling point.
i. They possess metallic lustre.
ii. They have high melting and boiling point.
8. (a) The element chlorine has atomic number 17 and atomic mass 35, calculate the number of protons, neutrons and electrons. Write one difference between octet and duplet rule. [2]
Answer
Number of electrons = Atomic number = 17
Number of protons = Atomic number = 17
Number of neutrons = Atomic mass — Number of protons
= 35-17
= 18
Difference between octet rule and duplet rule is as following:
Number of protons = Atomic number = 17
Number of neutrons = Atomic mass — Number of protons
= 35-17
= 18
Difference between octet rule and duplet rule is as following:
| Octet rule | Duplet rule |
| The natural tendency of an atom of an element to make 8 electrons in its valence shell by gaining, losing or sharing electrons between the combining atoms during the formation of molecules is called octet. | The natural tendency of an atom of an element to make 2 electrons in its valence shell by gaining, losing or sharing electrons between the combining atoms during the formation of molecules is called duplet. |
(b) What is chemical equation? Hydrogen and oxygen react to give water, write the word equation and chemical equation for it. [3]
Answer
A chemical reaction which is expressed by using molecular formulae of reactants and products is called chemical equation.
Word equation-
Hydrogen + Oxygen → Water
Chemical equation-
2H2 + O2 → 2H2O
Word equation-
Hydrogen + Oxygen → Water
Chemical equation-
2H2 + O2 → 2H2O
Group (Biology)
9. (a) Which organ of our body works the most? Write any two functions of that organ. Which plant tissue is responsible for the plant’s growth? [3]
Answer
The organ ‘Brain’ of our body works the most.
The function of brain is:
a. Thinking or cognition
b. Perception or sensing
Meristematic plant tissue is responsible for the plant’s growth.
(b) Write one function each of RBC, WBC and platelets. [3]
Answer
RBC: The function of RBC is to transport oxygen and carbon dioxide in our body.
WBC: The function of WBC is to fight against germs that cause diseases.
Platelets: The function of platelets is to protect the body from loss of blood.
WBC: The function of WBC is to fight against germs that cause diseases.
Platelets: The function of platelets is to protect the body from loss of blood.
10. (a) Explain, how could you prove experimentally that, oxygen gas is released during photosynthesis by green plants. [3]
Answer
Material required:
Beaker, funnel, test tube, hydrilla plant.
Procedure:
Take some healthy, fresh branches of hydrilla plant in a funnel and invert in a beaker. Put water in the beaker till the end of the funnel is under water as shown in figure. Take a test tube full of water and close its mouth with a thumb. Then invert it over the stem of funnel and release the thumb. Such method is applied so as to keep the test tube free of air. Keep the set undisturbed in the sunlight for a while.
Observation:
After a short time some bubble of gas in the test tube is produced. The gas so evolved is collected at the top of test tube. Take it out and bring burning match stick near the tube. The test-tube will steak light.
Figure in copy
Fig: Oxygen is evolved during photosynthesis.
Result
The evolved gas is oxygen which helps in burning.
Conclusion
O2 is evolved during photosynthesis.
Beaker, funnel, test tube, hydrilla plant.
Procedure:
Take some healthy, fresh branches of hydrilla plant in a funnel and invert in a beaker. Put water in the beaker till the end of the funnel is under water as shown in figure. Take a test tube full of water and close its mouth with a thumb. Then invert it over the stem of funnel and release the thumb. Such method is applied so as to keep the test tube free of air. Keep the set undisturbed in the sunlight for a while.
Observation:
After a short time some bubble of gas in the test tube is produced. The gas so evolved is collected at the top of test tube. Take it out and bring burning match stick near the tube. The test-tube will steak light.
Figure in copy
Fig: Oxygen is evolved during photosynthesis.
Result
The evolved gas is oxygen which helps in burning.
Conclusion
O2 is evolved during photosynthesis.
(b) Write two organs of nervous system with two functions. [2]
Answer
The two organs of nervous system are:
i. Brain
a. Thinking or cognition
b. Perception or sensing
ii. Spinal cord
a. Reflexes
b. walking
i. Brain
a. Thinking or cognition
b. Perception or sensing
ii. Spinal cord
a. Reflexes
b. walking
11. (a) What is a system? Mention a name of any one system of human body? [2]
Answer
A group of different organs which conducts a particular life process is called system. The name of one system of human body is skeletal system.
(b) Write in short about glandular epithelium. [3]
Answer
Glandular epithelium is a modification of columnar epithelium in which cells have become specialized for the manufacture or secretion of substances. These form the various glands of the body of vertebrate i.e. unicellular glands and multicellular glands. Unicellular glands are called single celled. The multicellular glands may be simple or compound cell.
Group (Astronomy and Geology)
12. (a) Describe the climatic condition of Terai and Himalayan Region of Nepal. [3]
Answer
The Terai Region of Nepal ranges from, 60 m to 1200m from sea level. Tropical climate is found in this region. Temperature reaches upto 40°C during summer and falls to 6°C during winter. Terai region remains usually warm. The soil is fertile and the forest is of ever green type.
The Himalayan Mountain ranges from 3300m to 5000m from the sea level. The temperature during the summer season reaches up to 15°C and falls below 0°C during the winter. The reason above 5000m is covered with snow throughout the year. No plants are found here. This is also called tundra climate.
The Himalayan Mountain ranges from 3300m to 5000m from the sea level. The temperature during the summer season reaches up to 15°C and falls below 0°C during the winter. The reason above 5000m is covered with snow throughout the year. No plants are found here. This is also called tundra climate.
(b) What is phase of the moon? Write any three bases of the evolution of living beings on the earth? [3]
Answer
Moon seems changing its shape that is seen from the earth is called phase of the moon.
The three bases of the evolution of living beings on the earth are:
i. Atmosphere with oxygen.
ii. Moderate temperature.
iii. Presence of water.
The three bases of the evolution of living beings on the earth are:
i. Atmosphere with oxygen.
ii. Moderate temperature.
iii. Presence of water.
Group (Environment Science)
13. (a) Sustainable development is important for our country. Explain. [3]
Answer
Nepal is a country rich in biodiversity. It consists of huge amount of natural resources. But we have been unable to utilize the resources. The natural resources are degrading day by day because of sadistic use of the available resources. Sustainable development helps to overcome these problems by helping to understand the limitation of the natural resources. It also promotes the maximum use of the available resources. Hence, sustainable development is very important for a diversified country like Nepal.
(b) Write the principles of Sustainable development. [2]
Answer
The principles of sustainable development are as follows:
i. Living within environmental limits
ii. Achieving sustainable economy
iii. Promoting good governance
iv. Using sound science responsibility
v. Ensuring a strong, healthy and just society
i. Living within environmental limits
ii. Achieving sustainable economy
iii. Promoting good governance
iv. Using sound science responsibility
v. Ensuring a strong, healthy and just society
14. (a) Differentiate between wildlife reserves and hunting reserves by any two points. [2]
Answer
The two differentiate between wildlife reserves and hunting reserves are:
Wildlife reserves | Hunting reserves |
A separate reserved area for protection and proper management o endangered wildlife is called wildlife reserved | The reserved area established for hunting and killing or capture is called hunting reserve. |
There are three wildlife reserves in Nepal. | There is only one hunting reserve in Nepal. |
(b) What is noise pollution? Write some causes of noise pollution. [2]
Answer
The undesirable increase in sound that disturbs the environment and people around it is called noise pollution. The causes of noise pollution are:
i. Honking of horns
ii. Sound from construction works
iii. People shouting
i. Honking of horns
ii. Sound from construction works
iii. People shouting
15. (a) How does human being depend on natural resources for their shelter? [2]
Answer
Man has moved from cave to tall buildings made of steel, iron, aluminium and other resources. Both types of house use natural resources. Hence, human being is completely dependent upon natural resources for shelter.
(b) Write short note on
i. Genetic diversity
ii. Proper use of resources
[2]
i. Genetic diversity
ii. Proper use of resources
[2]
Answer
i. Genetic diversity:
Genetic diversity is the variation in the hereditary unit that transfers parental characteristics to their offspring. It depends on the population of the organism.
ii. Proper use of resources :
The need to increase efficiency and productivity while preserving natural resources, especially water and soil, is great. In light of these realities, growers are under pressure to produce more, pollute less, fulfill consumer preferences, and make a living.
Genetic diversity is the variation in the hereditary unit that transfers parental characteristics to their offspring. It depends on the population of the organism.
ii. Proper use of resources :
The need to increase efficiency and productivity while preserving natural resources, especially water and soil, is great. In light of these realities, growers are under pressure to produce more, pollute less, fulfill consumer preferences, and make a living.