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Value Based Questions in Science for Class 10 Chapter 10 Light Reflection and Refraction

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Value Based Questions in Science for Class 10 Chapter 10 Light Reflection and Refraction

These Solutions are part of Value Based Questions in Science for Class 10. Here we have given Value Based Questions in Science for Class 10 Chapter 10 Light Reflection and Refraction

Question 1.
Rajesh is a student of class X and Ram is studying in class VII. Rajesh told Ram that he would show a magic to him. Rajesh had a lens. He focused the rays of sunlight on the bare arm of Ram. After few seconds, Ram felt pain and removed his arm away. Rajesh was laughing at Ram.

  1. Name the type of lens Rajesh had.
  2. Why did Ram feel pain ?
  3. Comment on the behaviour of Rajesh.

Answer:

  1. Convex lens
  2. When sun light is focused on the arm of Ram, heat is produced. This heat gave the . burning sensation to the skin of Ram’s arm,
  3. Rajesh should not have exploited the ignorance of Ram. He could have performed this magic on a black paper rather than the arm of Ram.

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Question 2.
A lady visited a shopping store with her friend. The owner of the store had fixed number of mirrors at different locations to monitor the activities of the customers. The lady picked up some items of make up and placed those items in her purse thinking that no one is watching her activity. But her friend asked her not to do so. The lady ignored her friend. When the lady came to the counter, the owner of the shop asked her to open her purse. She was humiliated in front of other customer and her friend.

  1. Name the type of mirrors fixed in the shop.
  2. Why was the lady asked by her friend not to place the make up items in her purse ?
  3. Why was the lady humiliated by the owner of the shop ?

Answer:

  1. Convex mirrors.
  2. The friend of the lady knew that stealing is crime.
  3. The lady had stolen the articles of owner of the shop.

Question 3.
Akhil, a student of class X went to an amusement park along with his younger brother. There, they entered in a small hall having number of large size mirrors. In front of one of the mirrors, they looked very funny. Their faces were normal, their bellies were fat and legs were short. Akhil’s younger brother was frightened and tried to hit the mirror with his foot. However, Akhil stopped him to do so.

  1. Name the type of mirror in front of which Akhil and his brother were standing ?
  2. What is the cause of the distortion of their images ?
  3. What values are shown by Akhil ?

Answer:

  1. The mirror was the combination of plane, concave and convex mirrors. The top most part was a plane mirror, the middle one was concave and the lower most was convex mirror.
  2. The refraction of light from mirrors distorted their images.
  3. Akhil knew that public or private property should not be damaged. Therefore, he stopped his brother to break the mirror.

Question 4.
Ram is a student of class X. His teacher told him that we can see stars clearly with the help of a telescope. He picked up the telescope from the lab and put it in his bag without telling the lab attendant. During night, he watched the stars and enjoyed.

  1. Name the lenses used in the telescope.
  2. Comment on the action of Ram.

Answer:

  1. Convex lenses.
  2. Ram has the curiosity to see stars with telescope. However, he should have asked his teacher or lab attendant to take the telescope to his home. He should be ashamed of his act as stealing is crime.

Hope given Value Based Questions in Science for Class 10 Chapter 10 Light Reflection and Refraction are helpful to complete your science homework.

If you have any doubts, please comment below. Learn Insta try to provide online science tutoring for you.

HOTS Questions for Class 10 Science Chapter 10 Light Reflection and Refraction

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HOTS Questions for Class 10 Science Chapter 10 Light Reflection and Refraction

These Solutions are part of HOTS Questions for Class 10 Science. Here we have given HOTS Questions for Class 10 Science Chapter 10 Light Reflection and Refraction

Question 1.
You have a spherical mirror. The image of an object placed in front of the mirror is virtual. If the position of the object is changed, the image remains virtual and erect. Is the spherical mirror concave or convex ?
Answer:
Since convex mirror always forms a virtual and erect image irrespective of the position of the object in front of the mirror. So the given spherical mirror is convex mirror.

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Question 2.
The following table gives the value of refractive indices of a few media.
HOTS Questions for Class 10 Science Chapter 10 Light Reflection and Refraction image - 1
Name the medium having highest optical density and a medium having lowest optical density.
(Similar to Text Book Question, CBSE 2012, 2016)
Answer:
Optical density of a medium is directly proportional to its refractive index. Therefore, diamond has the highest optical density and ice has the lowest optical density.

Question 3.
Refractive indices of kerosene, turpentine and water are 1.44, 1.47 and 1.333 respectively. Through which of these media, light travels fast ? Explain. (Similar to Text Book Question)
Answer:
HOTS Questions for Class 10 Science Chapter 10 Light Reflection and Refraction image - 2
Since, refractive index of water (1.333) is less than the refractive indices of kerosene and turpentine, so light travels faster in water than in kerosene and turpentine. Refractive indices of media A, B, C and D are given below :
HOTS Questions for Class 10 Science Chapter 10 Light Reflection and Refraction image - 3

Question 4.
In which of these four media is the speed of light  (i) maximum and (ii) minimum ? Find refractive index of medium D w.r.t. medium A. (New CBSE Sample Paper, CBSE 2011, 2013, 2016)
Answer:
HOTS Questions for Class 10 Science Chapter 10 Light Reflection and Refraction image - 4
Since, refractive index of medium A is the least, so speed of light in medium A is maximum.
Refractive index of medium D is the highest, so the speed of light in medium D is minimum.
HOTS Questions for Class 10 Science Chapter 10 Light Reflection and Refraction image - 5

Question 5.
The following table gives the values of refractive indices of a few media
HOTS Questions for Class 10 Science Chapter 10 Light Reflection and Refraction image - 6
Use this table to give an example of (i) a medium pair so that light speeds up when it goes from one of these media to another, (ii) a medium pair so that light slows down when it goes from one of these media to another. (CBSE Sample Paper 2008)
Answer:

  1. Light speeds up or speed of light increases when it travels from a medium of higher refractive index to a medium of lower refractive index. Therefore, speed of light increases when it travels from crown glass or water or from rock salt to water or from diamond to water.
  2. Light slows down or speed of light decreases when it travels from a medium of lower refractive index to a medium of higher refractive index. For example, when it travels from water to crown glass or from water to diamond.

Question 6.
Explain with the help of a diagram, why a pencil partly immersed in water appears to be bent at the water surface ? (CBSE (Delhi) 2008, 2011)
Answer:
It is due to the refraction of light.
HOTS Questions for Class 10 Science Chapter 10 Light Reflection and Refraction image - 7
Consider a pencil AB, such that CB portion of the pencil is immersed in water as shown in figure. Rays of light from the tip (B) of the pencil bend away from the normal as they go from water to air. The refracted rays appear to come from point B’. Thus, the immersed portion of pencil in water appears as CB’. Hence, the pencil appears to bent at the water surface. Moreover, the immersed portion of the pencil in water also appears to be shorter than the actual length of the pencil.

Hope given HOTS Questions for Class 10 Science Chapter 10 Light Reflection and Refraction are helpful to complete your science homework.

If you have any doubts, please comment below. Learn Insta try to provide online science tutoring for you.

NCERT Exemplar Solutions for Class 10 Science Chapter 14 Sources of Energy

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NCERT Exemplar Solutions for Class 10 Science Chapter 14 Sources of Energy

These Solutions are part of NCERT Exemplar Solutions for Class 10 Science. Here we have given NCERT Exemplar Solutions for Class 10 Science Chapter 14 Sources of Energy

Question 1.
Which of the following is a non-renewable source of energy ?
(a) Wood
(b) Sun
(c) Fossile fuels
(d) Wind
Answer:
(c).

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Question 2.
Acid rain happen because
(a) Sun leades to heating of upper layer of atmospher
(b) burning of fossil fuels release oxides of carbon, nitrogen and sulphur in the atmosphere
(c) electrical charges are produced due to friction amongst clouds
(d) earth atmosphere contains acids.
Answer:
(c).
Explanation : When oxides of carbon, nitrogen and sulphur react with water vapours in the atmosphere, they form carbonic acid, nitric acid and sulphuric acid respectively. These acids come down to the earth with rain.

Question 3.
The rain containing these acids is called acid rain.
Fuel used in thermal power plants is
(a) water
(b) uranium
(c) biomass
(d) fossil fuels
Answer:
(c).

Question 4.
In a hydro power plant
(a) Potential energy possessed by stored water is converted into electricity
(b) Kinetic energy possessed by stored water is converted into potential energy
(c) Electricity is extracted from water
(d) Water is converted into steam to produce electricity
Answer:
(a).
Explanation : Sequence of energy transformation in hydro power plant :

Question 5.
Potential energy of water stored in a dam Kinetic energy of falling water -» K.E. of rotation of turbine -> electrical energy. Which is the ultimate souce of energy ?
(a) Water
(b) Sun
(c) Uranium
(d) Fossil fuels
Answer:
(b).
Explanation : All forms of energy are derived from the sun.

Question 6.
Which one of the following of energy leads to least environmental pollution in the process of its harnessing and ultisation ?
(a) Nuclear energy
(b) Thermal energy
(c) Solar energy
(d) Geothermal energy
Answer:
(c).

Question 7.
Ocean thermal energy is due to
(a) energy stored by waves in the ocean
(b) temperature difference levels in the occean
(c) pressure difference at different levels in the ocean
(d) tides arising out in the ocean
Answer:
(b).

Question 8.
The major problem in harnessing nuclear energy is how to
(a) split nuclei ?
(b) sustain the reaction ?
(c) dispose off spent fuel safely ?
(d) convert nuclear energy into electrical energy ?
Answer:
(c).
Explanation : This is because even spent fuel (nuclear waste) continues to emit harmful radiation.

Question 9.
Which part of the solar cooker is responsible for green house effect ?
(a) Coating with black colour inside the box
(b) Mirror
(c) Glass sheet
(d) Outer cover of the solar cooker
Answer:
(c).
Explanation : Green house effect in a region occurs when heat radiation (infra-red radiation) are trapped in that region. When sunlight enters the solar cooker through a glass sheet, then the objects inside the solar cooker emit heat radiation (or infra-red radiation) due to their increased temperature. These radiations have long wavelengths and hence less energy. Therefore, they cannot pass through the glass sheet. Hence, interior of the solar cooker becomes warm due to the trapping of these radiation.

Question 10.
The main constituent of biogas is
(a) methane
(b) carbon dioxide
(c) hydrogen
(d) hydrogen sulphide
Answer:
(a).

Question 11.
The power generated in a windmill
(a) is more in rainy season since damp air would mean more air mass hitting the blades
(b) depends on the height of the tower
(c) depends on wind velocity
(d) can be increased by planting tall trees close to the tower
Answer:
(c).

Question 12.
Choose the correct statement
(a) Sun can be taken as an inexhaustible source of energy
(b) There is infinite storage of fossil fuel inside the earth
(c) Hydro and wind energy plants are non polluting sources of energy
(d) Waste from a nuclear power plant can be easily disposed off
Answer:
(a).

Question 13.
In a hydroelectric power plant more electrical power can be generated if water falls from a greater height because
(a) its temperature increases
(b) larger amount of potential energy is converted into kinetic energy
(c) the electricity” content of water increases with height
(d) more water molecules dissociate into ions
Answer:
(b).

Question 14.
Choose the incorrect statement regarding wind power
(a) It is expected to harness wind power to minimum in open space
(b) The potential energy content of wind blowing at high altitudes is the source of wind power
(c) Wind hitting at the blades of a windmill causes them to rotate. The rotation thus achieved can be ultilised further
(d) One possible method of ultilising the energy of rotational motion of the blades of a windmill is to run the turbine of an electric generator
Answer:
(b).

Question 15.
Choose the incorrect statement
(a) We are encouraged to plant more trees so as to ensure clean environment and also provide bio-mass fuel i
(b) Gobar-gas is produced when crops, vegetable wastes etc., decompose in the absence of oxygen
(c) The main ingredient of bio-gas is ethane and it gives a lot of smoke and also produces a log of residual ash
(d) Bio-mass is a renewable source of energy
Answer:
(c).

Question 16.
Why is there a need to harness non-convential sources of energy ? Give two main reasons.
Answer:

  1. Non-conventional sources of energy are pollution free, whereas fossil fuels cause lot of pollution.
  2. Non-conventional sources of energy are in exhaustible, whereas fossil fuels are limited.
  3. Our demand of energy is increasing day by day.

Question 17.
Write two different ways of harnessing energy from occean.
Answer:

  1. Tidal energy.
  2. Ocean Thermal energy (OTEC).

Question 18.
What steps would you suggest to minimise environmental pollution caused by burning of fossile fuel ?
Answer:
We can minimize environmental pollution caused by the burning of fossil fuel by

  1. growing more and more trees,
  2. Using smokeless chulahs and
  3. smokeless chimneys in thermal power plants.

Question 19.
What is the role of a plane mirror and a glass sheet in a solar cooker ?
Answer:
A solar cooker covered by a plane glass slab will be more efficient.
This is because glass slab does not allow the heat radiation to escape from the solar cooker and hence the temperature of the solar cooker covered with glass slab increases more than the temperature of the solar cooker which is left open.

Question 20.
Mention three advantages of a solar cell ?
Answer:
Advantages of Solar Cells

  1. They directly convert solar energy into electrical energy.
  2. They are environment-friendly i.e. they do not cause pollution.
  3. They are used to operate electric bulbs and tubes in remote areas where hydro—electricity is not available.

Question 21.
What is biomass ? What can be done to obtain bio-energy using biomass ?
Answer:
A material which contains carbon and other combustible materials is called biomass. The waste of plants and animals is the example of bio mass. (CBSE Papers)

Question 22.
What are the limitation in obtaining energy from wind ?
Answer:

  1. We cannot depend upon wind energy as it is available only when air is in motion. The appliances or machines operating with wind energy stop working as soon as wind stops. The minimum speed of wind to operate generator to produce electricity is about 15 km/h. As soon as the speed of the wind becomes less than 15 km/h, the generator stops working.
  2. There are certain regions where wind is not available, so the use of wind energy is limited to certain places where wind is in plenty and blows most of the time.
  3. Wind energy is not sufficient to operate very heavy machines.
  4. Wind energy cannot be used to operate all types of machines.
  5. Wind mills are usually broken during storms and hence lot of money is spent for the maintenance of a wind energy form.

Hope given NCERT Exemplar Solutions for Class 10 Science Chapter 14 Sources of Energy are helpful to complete your science homework.

If you have any doubts, please comment below. Learn Insta try to provide online science tutoring for you.

Value Based Questions in Science for Class 10 Chapter 14 Sources of Energy

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Value Based Questions in Science for Class 10 Chapter 14 Sources of Energy

These Solutions are part of Value Based Questions in Science for Class 10. Here we have given Value Based Questions in Science for Class 10 Chapter 14 Sources of Energy

Question 1.
Students of a school X’ visited nearby villages to educate people regarding the use of clean fuel for cooking and heating water. They told people not to use wood as fuel as it pollutes environment and the health of the people is at risk. They urged people to use LPG and solar cookers for cooking their food. They also requested villagers to grow more trees around their villages.

  1. What is the main disadvantage of using wood as a fuel ?
  2. What values are shown by students ?

Answer:

  1. Burning of wood causes air pollution, which leads to many diseases in human beings.
  2. Students show their concern for air pollution which is harmful for living beings. They want to preserve eco-system by growing more trees and making environment free from air pollution.

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Question 2.
Students of a school organised a debate. The topic of the debate was “should we go for macro hydro electric power plants or micro hydro electric power plants”. Some participants spoke in favour of macro hydro electric power plants and some in favour of micro hydro electric power plants. The students who spoke in favour of micro hydroelectric power plants argued that large area of fertile land can be saved. The problem of rehabilitating the population can be solved and a variety of flora and fauna can be saved.

  1. What are the disadvantages of constructing big dams for macro hydro electric power plants ?
  2. What values are shown by students in favour of micro hydro electric power plants ?

Answer:

    1. Large area of fertile land is submerged in water,
    2. People residing near the site of big dams are dislocated and find it difficult to settle elsewhere,
    3. Variety of flora and fauna is destroyed.
  2. Students in favour of micro hydro electric power plants are concerned about
    1. the loss of fertile land.
    2. the problem faced by people who loses their land and homes i.e., the problem of rehabilitation and
    3. the loss of flora and fauna, essential for preserving eco-system.

Question 3.
Most of people in a village were suffering from breathing problem and other diseases. Students of that village were quite worried about the health problem of their parents and neighbours. They realised that these problems were due to environmental pollution caused by burning of wood and cow dung cakes in the village. They requested their elders to use smokeless chulahs and construct bio gas plants. Villagers asked students from where money will come to purchase smokeless chulahs and to construct bio gas plant. Students told them that Govt, provides financial help for all these things. The villagers are now using bio gas for cooking food as they have constructed a common bio gas plant. The village is now neat and clean, as all the garbage in the village is used in bio gas plant. The patients are now recovering fast from their ailments.
Now answer the following questions based on the above paragraph.

  1. What are the disadvantages of burning wood and cow dung cakes ?
  2. What values are shown by students of the village ?

Answer:

  1. Environmental pollution is caused by burning wood and cow dung cakes. This pollution is the major cause of many diseases.
  2. Students are well informed about the different schemes launched by Govt, for the welfare of public. They feel concern about the welfare of their parents and neighbors. They know the importance of the cleanliness for a good health.

Question 4.
What steps would you suggest to the public to reduce energy consumption to meet the increasing demand of energy ?
Answer:

  1. Electric bulbs, tubes, fans and other appliances should be switched off as soon as you leave your room.
  2. The engines of the vehicles should be switched off when they are stopped for more than a minute.
  3. There should be minimum use of halogen lamps and decorative lights in shops and show rooms.
  4. Very old machinery should not be used in factories.

Question 5.
What steps would you suggest to control environmental pollution at local level ?
Answer:

  1. Use of smokeless chulahs,
  2. Use of bio-gas,
  3. Cleanliness drive in the community,
  4. No use of plastic bags,
  5. Plantation camps.

Question 6.
Aditya suggests his family to install a solar water heater at their residence. But some of the family members were in a favour of installing an electric geyser.
(a) Who according to you is taking a correct decision ? Mention the value exhibited by Aditya.
(b) Also give reasons (at least 2) for your answer. (CBSE 2013)
Answer:
(a) Aditya: Aditya was in favour of using renewable sources of energy.
(b)

  1. The use of renewable sources of energy will save the non-renewable sources of energy for future.
  2. The use of renewable sources of energy is eco-friendly.

Question 7.
Recently when Government decided to set up a nuclear power plant in an area, NGOs and local people raised their voice against it. They demanded that the Government should assure safety measures before setting up such a plant and Government assured them of it.
(a) Explain the value exhibited by people of the area.
(b) List any two concerns of the people for which they were demanding safety measures.(CBSE 2013)
Answer:
(a) People are concerned about their health.
(b) In a nuclear power plant, nuclear radiation are emitted. These radiation are very harmful to the living organism. They cause diseases like cancer, lukemia and blindness.

Question 8.
There was a poster making competition in a school on a topic ‘SAVE ENERGY’. The students were also asked to give write ups on this topic.
A student of the school is unable to make the write up on ‘SAVE ENERGY’.
(a) Suggest him two steps of ‘SAVE ENERGY’ ?
(b) Mention the value which the school is trying to give its students by holding such a competition. (CBSE 2013)
Answer:
(a)

  1. Electric bulbs, tubes, fans, heaters etc. must be switched off when you leave the room or office.
  2. There should be minimum use of halogen lamps and decorative lights in shops and showrooms as these devices consume large amount of electricity.
  3. The use of renewable sources of energy must be encouraged.

(b) School is trying to bring the awareness among students about the importance of energy for the development of the nation.

Question 9.
Ravi was using calculator to do some calculations. While doing so his calculator stopped working. He kept the calculator near the window for some time, exposed to sunlight. After some time he could use the calculator again. His friend Mohit who was using a battery operated calculator, watched him and told him that his calculator was better in the sense that he could immediately recharge the calculator by charging battery but Ravi was not convinced. He explained to Mohit the advantages of solar calculator and convinced him to adopt it.
(a) State the values exhibited by Ravi.
(b) List the advantages of using a calculator driven by solar energy which convinced Mohit too to adopt it. (CBSE 2013)
Answer:
(a) Ravi has high degree of general awareness. He has leadership like qualities to convince others.
(b)

  1. A calculator driven by solar energy is cheap as it can be recharged just by exposing to sunlight for sometime.
  2. Solar cells used in calculators do not cause pollution.

Question 10.
Ravi convinced his entrepreneur friend to set up solar panels instead of setting a thermal power plant. His friend agreed to his proposal and with the help of the cooperative bank he succeeded in doing so in the village nearby.
(a) What values would you appreciate in Ravi as well in his friend ?
(b) Why do you think Ravi thought harnessing solar energy is a better option ? (CBSE 2013)
Answer:
(a) Ravi has high degree of general awareness. He is concerned with the welfare of his friend. The friend
of Ravi has the quality to listen to others and he believes in logic.
(b)

  1. Solar energy causes no air pollution while thermal power plant leads to air pollution.
  2. Setting up a thermal power plant may be opposed by local people as it affects their health due to
    air pollution.
  3. Thermal power plant requires coal and oil i.e., non-renewable sources of energy. These sources of energy are costly and may be exhausted one day. On the other hand, solar panels require renewable source of energy i.e., the sunlight. It is free of cost and will not be exhausted in near future.

Question 11.
Mr. Chopra forms an NGO and he approaches municipal corporation of a city. He puts a proposal to the corporation that his NGO would collect the waste material and garbage of the city at a particular area and promises them to supply electricity for street lights. In return the corporation has to pay them a nominal amount. The corporation accepted his proposal.
(a) Explain the value exhibited by Mr. Chopra,
(b) Explain two advantages that accrued to the city by accepting the proposal of Mr. Chopra. (CBSE 2014)
Answer:
(a) Mr. Chopra is innovative and he is concerned to the cleanliness of the city.
(b)

  1. City would become clean and there will be no fear of spreading diseases in the city.
  2. The corporation will save money as it has to pay nominal amount for getting electricity from Mr. Chopra’s NGO. The conventional electricity which corporation receives from Electricity Board is costly.

Question 12.
Harsh, Nikhil and Neha come to school by their respective cars though they lived within a distance of 2 km from the school. On the other hand Raghu, their friend, came by bicycle from the same distance. He persuaded his friends to stop coming by car and use cycle instead. His friends were convinced and they also started coming by bicycle.
(a) List the values exhibited by Raghu.
(b) Explain how he must have convinced his friends to adopt same values that they accepted his proposal. (CBSE 2014)
Answer:
(a) Raghu has leadership like qualities to convince others and take others into his confidence.
(b) He must have convinced his friends by telling them about the harmful effect caused by pollution due to the burning of fuel used in cars. Moreover, he must have told his friends about the importance of saving energy for future.

Question 13.
Traffic jams, outside the school gate was a common sight since most of the students came on their own cars. This became a topic for discussion on every RT.A. meeting. On one such RT.A. meeting, the principal pointed out the examples of four of their teachers who were car pooling for the past several years. She asked the parents also to adopt this method to sort out the problem.
(a) List two values shown by the teachers mentioned by the Principal.
(b) Explain two advantages that will occur if more parent emulated the example of these teachers. (CBSE 2015)
Answer:
(a)

  1. Teachers have leadership like qualities to take initiative to solve problems like traffic jams on roads and to save fuel as well as money for future.
  2. They wanted to decrease the pollution caused by burning of fuel used in cars.

(b)

  1. The problem of traffic jams outside the school gate as well as on the roads will be solved,
  2. A large amount of money as well as fuel will be saved for future.
  3. The economic condition of most of the parents will be improved,
  4. Pollution caused by burning of fuel used in cars will also decreases.

Question 14.
Arun lives in an eco-friendly house. All rooms in his house are cross ventilated and well lit with sun’s light. He has installed solar panels on roof top and also uses solar devices like solar cooker, solar water heater etc. Although he has spent some more money initially on these installations, yet he is happy now.

  1. State the reason behind Aran’s happiness,
  2. Which element is used in fabricating solar cells ?
  3. What inspirations should we take from Arun ? (C.B.S.E. 2015)

Answer:

  1. Except initial cost of installations of solar panels, Arun was getting energy to operate solar devices free of cost.
  2. Silicon element is used in fabricating solar cells.
  3. We should go for non-conventional sources of energy like solar energy and wind energy. These sources of energy are eco-friendly as they do not cause any pollution.

Hope given Value Based Questions in Science for Class 10 Chapter 14 Sources of Energy are helpful to complete your science homework.

If you have any doubts, please comment below. Learn Insta try to provide online science tutoring for you.

HOTS Questions for Class 10 Science Chapter 14 Sources of Energy

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HOTS Questions for Class 10 Science Chapter 14 Sources of Energy

These Solutions are part of HOTS Questions for Class 10 Science. Here we have given HOTS Questions for Class 10 Science Chapter 14 Sources of Energy

Question 1.
Following model demonstrates the process of thermo-electric production.
HOTS Questions for Class 10 Science Chapter 14 Sources of Energy image - 1

  1. Identify and label the device marked as 1.
  2. Why is tennis ball fitted with metal sheets rotated ?
  3. Name the device, which depends on the principle demonstrated by this model.
  4. Which form of energy is converted into electrical energy ?

Answer:

  1. Device 1 is a dynamo.
  2. Tennis ball fitted with metal sheets rotates due to the force exerted on it by the steam.
  3. Thermal power plant works on the principle demonstrated by the given model.
  4. Mechanical energy of tennis ball fitted with metal sheets is converted into electrical energy.

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Question 2.
A diagram shown below is a biogas plant.
HOTS Questions for Class 10 Science Chapter 14 Sources of Energy image - 2

  1. Identify the parts indicated by question marks and labelled 1, 2, 3 and 4 in the diagram.
  2. Name the micro organisms responsible for the fermentation of the slurry in the digester.
  3. Name two chemical elements present in the manure or spent slurry.

Answer:

    1. Slurry of cattle dung and water
    2. Gas tank containing bio-gas.
    3. Digester.
    4. Spent slurry or manure
  2. Anaerobic micro organisms,
  3. Nitrogen and phosphorous are present in the manure.

Question 3.
A student constructed a box type solar cooker. He found that it did not work efficiently. What could this be due to ? Give any four possible mistakes in the solar construction and operation of the cooker. What maximum temperature can ordinarily be reached inside a solar cooker ? (CBSE 2010)
Answer:
He might be committing the following mistakes :

  1. He might have not blackened the interior of the solar cooker,
  2. He might be using a plastic cover instead of a glass cover,
  3. He might have not made it insulated,
  4. He might have not used black containers. Maximum temperature attained in a solar cooker is about 140° C.

Question 4.
A student has set up a solar cooker in a box by using a black painted aluminium sheet, a black cooking vessel, some glass wool, a glass sheet and a mirror plate. What is the role of each item used in the solar cooker ?
Answer:
Black painted aluminium sheet absorbs heat radiation.
Black cooking vessel also absorbs heat radiation to cook food.
Glass wool prevents the loss of heat.
Glass sheet prevents the escape of heat radiation from the box.
Mirror plate reflects the sunlight to fall on the glass sheet.

Hope given HOTS Questions for Class 10 Science Chapter 14 Sources of Energy are helpful to complete your science homework.

If you have any doubts, please comment below. Learn Insta try to provide online science tutoring for you.