SEE 2075 (2019) RE-111’AP’ (Solved Question Paper)
Group A
a) What is free fall?
Answer: Free fall is a condition when a body falls down only under the influence of acceleration due to gravity.
b) State the law of floatation.
Answer: The law of floatation states, “A body floats on a liquid if it can displace the weight of liquid equal to its own weight.”
c) Define heat energy in terms of kinetic energy of molecules.
Answer: In terms of kinetic energy of molecules, heat energy is defined as the sum of kinetic energy of all the molecules present in a body.
d) Where should be object kept in front of convex lens to get magnification 1?
Answer: The object should be kept at 2F in front of convex lens to get magnification 1.
e) Write the name of high-quality coal.
Answer: The name of high-quality coal is Anthracite.
f) Define promotor.
Answer: Promotor is a chemical substance added to a catalyst to increase activity.
g) What is an alkali?
Answer: The base that gets dissolved in water is called an alkali.
h) Write any two ores of silver.
Answer: Any two ores of silver are Horn Silver and Argentite.
i) Write two examples of the thermosetting plastic.
Answer: Any two examples of thermosetting plastic are: Bakelite and Melamine.
j) Write the main function of the insulin hormone.
Answer: The main function of the insulin hormone is to decrease sugar level in blood.
k) What is blood pressure?
Answer: Blood pressure is the pressure exerted by the blood on the inner-walls of arteries.
l) Write two effects seen from Klinefelter’s disorder.
Answer: Any two effects seen from Klinefelter’s disorder are:
a) Longer arms
b) Abnormally tall
m) Write the name of upper part and lower part used in grafting.
Answer: In grafting, the name of upper part is scion and that of the lower part is stock.
n) Define monohybrid cross.
Answer: The crossing between two organisms having one pair of contrasting characteristics is defined as monohybrid cross.
o) What is fossil?
Answer: Fossil is the dead remains of the plants and animals preserved under the rocks for millions of years.
Group B
2) What happens to balloon filled with air, when it goes very high altitude from the surface of the earth? Why?
Answer: When the balloon filled with air goes to very high altitude from the surface of the earth, it stops moving and stays stationary at a point.
It is because the upthrust provided by the air becomes less than the weight of the balloon at a certain height. As a result, it cannot ascend from that height neither it can descend, too.
3) Gobar gas is more beneficial in rural areas of Nepal. Give two reasons.
Answer: Gobar gas is more beneficial in rural areas of Nepal because of the following reasons:
- In rural areas, people do farming and animal rearing. Wastes generating from such activities is perfect raw material for production of gobar gas. So, it is economic.
- Gobar gas is alternative and environment-friendly source of energy and burns completely without smoke.
4) Nowadays clinical thermometer is replaced by digital thermometer, why?
Answer: Digital thermometers display the readings as a combination of certain digits and the data are mostly accurate. While in a clinical thermometer, users had to read the data through the scale. Such reading taken could be inaccurate because of the fault in viewing angle. So, nowadays clinical thermometer is replaced by digital thermometer.
5) Write any two reasons for using nichrome wire as a heating element.
Answer: Following are the two reasons for using nichrome wire as a heating element:
- It is a very good conductor of heat and has very high melting point.
- It has very high resistivity to electric current as well.
6) Write a chemical reaction between Calcium and Sulphuric acid. Mention the type of chemical reaction.
Answer: The reaction between Calcium (Ca) and Sulphuric acid (H2SO4) is given below:
$\text{Ca + H}_2\text{SO}_4 \arrow \text{CaSO}_4 + \text{H}_2$
It is a single displacement reaction.
7) Write any two differences between PVC and Bakelite.
Answer: Any two differences between PVC and Bakelite are:
| PVC | Bakelite |
| 1) PVC is a thermoplastic whose shape can be changed easily on heating. | 1) Bakelite is a thermosetting plastic that has a very rigid shape. |
| 2) It melts on increasing heat. | 2) It can resist melting when subjected to increasing temperature up to a great extent. |
8) Though hydrochloric acid is formed inside our body, it is called inorganic acid. Why?
Answer: Organic compounds generally contain Carbon as their major constituent. However, hydrochloric acid is composed of only Hydrogen and Chlorine. Therefore, it is called inorganic acid.
9) In general, iron is not used to make body parts of aeroplane. Why? Give any two reasons.
Answer: Iron is not used to make body parts of aeroplane because of the following reasons:
- Iron is a heavy metal as compared to the other metals used to build aeroplane.
- Iron faces rusting when exposed to moisture and air for a longer time.
10) Write any two reasons that silk worm is useful insect.
Answer: Silkworm is a useful insect because of the following reasons:
- Sericulture – rearing of silkworm, has become a profession of many and has been generating a reliable source of income.
- Silkworm produces silk which can be used to design silk clothes that are lustrous.
11) A cell of girl contains 45, XO chromosomes, which type of chromosome disorder is present in her body? Write any one symptom of it.
Answer: If the cell of the girl contains 45, XO chromosomes, then it is Turner’s syndrome. One symptom of Turner’s syndrome is Less developed ovaries.
12) Write any two differences between binary fission in amoeba and budding in yeast.
Answer: Any two differences between binary fission in amoeba and budding in yeast are:
| Binary Fission in Amoeba | Budding in Yeast |
| It is process where a single parent amoeba separates into two daughter amoebae. | It is a process by which multiple offsprings of yeast are produced. |
| The nucleus elongates and divides first. | The nucleus gets divided after the formation of bud. |
13) Offsprings obtained from same parents show some similarities but they are not exactly similar to each other? Why? Write with reason.
Answer: An offspring inherits few characteristics from the mother and few from the father. Two offsprings might not acquire the identical characteristics from the same parents due to variation in the dominant and recessive characteristics carried by the chromosomes involved during sex determination.
14) Write any two applications of artificial satellites.
Answer: Any two applications of artificial satellites are:
- They are used as boundless communication media to share news and data live.
- They are used by nations to spy on their enemies.
Group C
15) A stone dropped freely from 72 m height of tower and reaches the ground in 6 seconds. Calculate acceleration due to gravity on that stone. At what condition does the acceleration due to gravity becomes zero?
Solution:
Given,
Height of tower (h) = 72 m
Time taken by stone to reach the ground (t) = 6 s
Initial velocity (u) = 0 m/s
To find: acceleration due to gravity (g) = ?
We know,
Hence, the required acceleration due to gravity acting on the stone was 4 ms-2.
Acceleration due to gravity becomes zero when there is an acceleration equal to acceleration due to gravity but in upwards direction.
16) If a heater with power 2000 W runs one hour, it gives 4.2*103 kJ heat. What will be the temperature increased in 20kg of water with temperature 40oC by that heat? (Specific heat capacity of water = 4200 J/kgoC)
Solution:
Given,
Amount of heat (Q) = 4.2*103 kJ
Mass of water (M) = 20 kg
Initial temperature (θ1) = 20oC
Specific heat capacity of water (s) = 4200 J/kgoC
To find: final temperature of water (θ2) = ?
We know,
Hence, the required final temperature of the given water is 70oC.
17) Draw a diagram of laboratory preparation of ammonia gas and label any four parts. Why this gas cannot be collected in the gas jar by downward displacement of water?
Answer: Laboratory preparation of ammonia gas:
Correction: Mixture (Maxture)
Ammonia gas cannot be collected in the gas jar by downward displacement of water because it is highly soluble in water and forms ammonium hydroxide on reaction.
18) Which compound is represented by the general formula CnH2n+1OH? If value of n is 2 in this formula which compound is formed? Write its structural formula. If OH of this compound is replaced by H which compound is formed? Write its name and molecular formula.
Answer: By the general formula CnH2n+1OH, organic compound Alcohol is represented.
In the above general formula, when n =2, we have, C2H5OH, this compound is ethyl alcohol or ethanol. Structural formula of ethanol is as follows:
Figure: Ethanol Structural Formula
When OH is replaced by H, we receive C2H6, which is ethane.
19) Draw a diagram of different parts of the brain. Damage of which part causes sudden death? Show this part in the diagram.
Answer:
Figure: Human Brain (Correction: Medvilla as Medulla) Source: Science Textbook GON
Damage of Medulla oblongata causes sudden death.
20) Write any three applications of forests in our daily life.
Answer: Any three applications of forests in our daily life are:
- It provides us firewood, timber and raw materials for furniture.
- It regulates the air in the atmosphere by absorbing carbon dioxide gas and evolving oxygen gas.
- It acts as a centre of attraction for wildlife photography, videography and is a stable source of income.
21. Study the given diagram and answer the following questions:
a) What type of defect of vision is the diagram of the eye?
Answer: In the diagram of the eye, Myopia is the defect of vision illustrated.
b) What is the cause of the defect of the vision?
Answer: The cause of the defect of this vision is due to decrease in focal length of the eye or due to elongation of the eye ball.
c) What is to be done to remedy such defect?
Answer: Spectacles with convex lens of proper power should be used to remedy such effect.
d) Draw a diagram to show the remedy of this defect.
Answer: Following is the diagram:
Source: Science Textbook 10, GoN
22. Study the given table and answer the following questions:
| Name of Elements | Electronic Configuration |
| A | 1s2,2s2,2p6,3s2 |
| B | 1s2,2s2,2p6,3s2,3p5 |
| C | 1s2,2s2,2p6,3s2,3p6,4s1 |
- Write the name of elements indicated by A and B.
Answer: The name of elements A and B are Magnesium (Mg) and Chlorine (Cl). - Keeping Aluminium instead of A, which product would you expect when it reacts with B? Write molecular formula of it.
Answer: If element A is Aluminium then on reaction with B i.e., Chlorine, we can expect Aluminium Chloride as the product. Its molecular formula is .
- Write valency of element C and chemical nature of it.
Answer: The valency of element C is 1. It is an electropositive element (metal).
- Write the balanced chemical equation when ‘C’ reacts with ‘B’.
Answer: Element C is Potassium (K) and B is Chlorine (Cl). When they combine together, the following reaction takes place:
23. Blood cells contained in normal blood of human is shown in chart. Study it and answer the following questions.
| Blood Cells | Number in 1mm3 |
| A | 4000-11000 |
| B | 200 000 – 400 000 |
| C | 4 500 000 – 5 00 000 |
- Name A, B, and C.
Answer: The names of A, B and C are White Blood Cells, Platelets and Red Blood Cells, respectively.
- Which disease may occur if A is present in more number in blood?
Answer: If A is present in more number in blood, the person suffers from Leukocytosis.
- Which disease may occur if C is present in less number in blood?
Answer: If C is present in less number in blood, the person suffers from anaemia.
- If a man cuts his hand and blood does not clot, which one is present in less in blood among A, B, and C?
Answer: If a man cuts his hand and blood does not clot, among A, B, and C; B is present in less amount in the blood of the man.
24. Consequences like skin burn and skin cancer were observed when people take sunbath on earth surface. On the basis of it answer the given questions.
- What is the cause of it?
Answer: It is caused by the depletion of ozone layer. Due to this, the harmful ultraviolet rays enter the Earth and adversely impact our health.
- What is to be done for the control of it?
Answer: In order to control it, the depletion of ozone layer should be controlled. For this, the production of Chlorofluorocarbons (CFCs), Oxides of Nitrogen, Sulphur, etc. should be minimized.
- In such condition, what is the temperature on environment? Write any two effects.
Answer: Ozone layer is also responsible for maintaining the temperature of the Earth. When it is depleted, the temperature of environment increases. Following are its two effects:
- Snow-capped mountains start to melt and there is high possibility of Glacial Lake Outburst Flood.
- As the melted ice enters oceans, people residing in islands are in a danger of being sub-merged due to increased level of water.
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