CBSE Class 10

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).

More Resources

• NCERT Exemplar Solutions for Class 10 Science
• NCERT Solutions for Class 10 Science
• Value Based Questions in Science for Class 10
• HOTS Questions for Class 10 Science
• Previous Year Question Papers for CBSE Class 10 Science

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

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.

More Resources

• Value Based Questions in Science for Class 10
• HOTS Questions for Class 10 Science
• NCERT Solutions for Class 10 Science
• NCERT Exemplar Solutions for Class 10 Science
• Previous Year Question Papers for CBSE Class 10 Science

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. 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

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.

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.

More Resources

• HOTS Questions for Class 10 Science
• NCERT Solutions for Class 10 Science
• Value Based Questions in Science for Class 10
• NCERT Exemplar Solutions for Class 10 Science
• Previous Year Question Papers for CBSE Class 10 Science

Question 2.
A diagram shown below is a biogas plant.

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. 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.

NCERT Exemplar Solutions for Class 10 Science Chapter 13 Magnetic Effects of Electric Current

These Solutions are part of NCERT Exemplar Solutions for Class 10 Science. Here we have given NCERT Exemplar Solutions for Class 10 Science Chapter 13 Magnetic Effects of Electric Current

Question 1.
Choose the incorrect statement from the following regarding magnetic lines of field.
(a) The direction of magnetic field at a point is taken to be the direction in which the north pole of a magnetic compass needle points.
(b) Magnetic field lines are closed curves.
(c) If magnetic field lines are parallel and equidistant, they rep-resent zero field strength.
(d) Relative strength of magnetic field is shown by the degree of closeness of the field lines.
Answer:
(c).
Explanation : Magnetic field lines which are parallel and equidistant represent uniform magnetic field.

More Resources

• NCERT Exemplar Solutions for Class 10 Science
• NCERT Solutions for Class 10 Science
• Value Based Questions in Science for Class 10
• HOTS Questions for Class 10 Science
• Previous Year Question Papers for CBSE Class 10 Science

Question 2.
If the key in the arrangement shown in figure is taken out (the circuit is made open) and magnetic field lines are drawn over the horizontal plane ABCD, the lines are
(a) concentric circles
(b) elliptical in shape
(c) straight lines parallel to each other
(d) concentric circles near the point O but of elliptical shapes as we go away from it
Answer:
(c).

Explanation : When no current flows through the wire, mag¬netic field lines over the plane ABCD will represent magnetic field of the earth. These field lines are straight lines parallel to each other.

Question 3.
A circular loop placed in a plane perpendicular to the plane of paper carries a current when the key is ON. The current is seen from points A and B (in the plane of the paper and on the axis of the coil) is anticlockwise and clockwise respectively. The magnetic field lines point from B to A. The N-pole of the resultant magnet is on the face close to
(a) A
(b) B
(c) A if current is small, and B if current is large.
(d) B if the current is small, and A if current is large.

Answer:
(a).
Explanation : If current seems to flow in anticlockwise direction in a coil, then that face of the coil acts as N-pole.

Question 4.
In a long straight solenoid, N-and S-poles are created at the two ends of the solenoid. Which of the following statements is incor¬rect ?
(a) The field lines inside the solenoid are in the form of straight lines indicating that magnetic field is same at ail points inside the solenoid.
(b) The pattern of the magnetic field associated with the solenoid is different from the pattern of the magnetic field around a bar magnet.
(c) N-and S-poles exchange positions when the direction of the current through the solenoid is reversed.
(d) Magnetic field produced inside the solenoid can be used to magnetise a bar of magnetic material like soft iron, when placed inside the solenoid.
Answer:
(b).
Explanation : The pattern of magnetic field produced by a cur¬rent carrying solenoid resembles with the pattern of magnetic field of a bar magnet.

Question 5.
A uniform magnetic field exists in the plane of paper pointing from left to right as shown in figure. In the field, an electron and a proton move as shown. The electron and proton experience

(a) forces, both pointing into the plane of paper
(b) forces, both pointing out of the plane of paper
(c) forces, pointing into the plane of paper and out of the plane of paper respectively.
(d) forces, pointing opposite and along the direction of the uniform magnetic field respectively.
Answer:
(a).
Explanation : Apply Fleming’s left hand rule and considering the flow of current in the direction of the movement of proton and in the direction opposite to the movement of electron.

Question 6.
Commercial electric motors do not use
(a) an electromagnet to rotate the armature
(b) effectively large number of turns of conducting wire in the current carrying coil
(c) a permanet magnet to rotate the armature id a soft iron on which the coil is wound.
Answer:
(c).
Explanation : In commercial motor, armature rotates in the mag-netic field produced by an electromagnet. The strength of such magnetic field can be increased to the desired value. However, a permanent magnet provides a fixed and weak magnetic field.

Question 7.
Figure shows the arrangment of two coils wound on a non-conducting cylindrical rod. The plugh of the key is then in¬serted and later removed.

(a) Deflection in the galvanometer remains zero throughout
(b) There is momentary deflection in the galvanometer that dies out shortly and deflections in both the cases are in the same direction
(c) There is momentary deflection in the galvanometer that dies out shortly and there is no effect when the key is re¬moved
(d) There are momentary deflections in both the cases that die out shortly but the deflections are in apposite directions.
Answer:
(a).
Explanation : Due to electromagnetic induction, induced cur¬rent flows in the coil with which galvanometer is connected, when the key is inserted (i.e. current grows in the primary coil) and when the key is removed (i.e. current decays in the primary coil).

Question 8.
Choose the incorrect statement
(a) Fleming’s right hand rule is a simple rule to know the direction of induced current.
(b) The right-hand thumb rule is used to find the direction of magnetic fields due to current carrying conductors.
(c) The difference between the direct and alternating currents is that the direct current always flows in one direction, whereas the alternating current reverses its direction periodically.
(d) In India, the AC changes direction after every 1/60 seconds
Answer:
(d).
Explanation : Frequency of AC in India = 50 Hz
∴ AC completes 1 cycle in 1/50 seconds.
In one cycle, AC changes direction two times. Hence, time after which AC changes direction

Question 9.
A constant current flows in a horizontal wire in the plane of the paper from east to west as shown in figure. The direction of magnetic field at a point will be north to south.

(a) directly below the wire
(b) directly above the wire
(c) at a point located in the plane of the paper, on the north side of the wire
(d) at a point located in the plane of the paper, on the south side of the wire.
Answer:
(d).
Explanation : Applying right hand thumb rule to know the direction of the magnetic field.

Question 10.
The strength of magnetic field inside a long current carrying straight solenoid is
(a) more at the ends than at the centre
(b) minimum in the middle
(c) same at all points
(d) found to increase from one end to the other.
Answer:
(c).
Explanation : Magnetic field inside a long current carrying straight solenoid is uniform.

Question 11.
To convert AC generator to DC generator
(a) slip rings and brushes must be used ‘
(b) split ring type commutator must be used
(c) rectangular wire loop is to be used
(d) stronger magnetic field is to be used.
Answer:
(b).

Question 12.
The most important safety device method used for protecting electrical appliances from short circuiting or overloading is
(a) earthing
(b) use of stabilizers
(c) use of electric meter
(d) use of fuse.
Answer:
(d).
Explanation : Fuse melts and the circuit breaks as soon as the current in the circuit exceeds safe limit.

Question 13.
A magnetic compass needle is placed in a plane of paper near point A as shown in figure.
In which plane should a straight current carrying conductor be placed so that it passes through A and there is no change in the deflection of the compass ? Under what condition is the deflection maximum and why?

Answer:
The straight current carrying conductor should be placed in the plane of the paper. The deflection of the compass is maxi¬mum when the conductor passes through A and perpendicular to the plane of the paper. The magnetic field due to current carrying conductor is maximum in the plane of the paper.

Question 14.
Under what conditions permanent electromagnet is obtained if a current carrying solenoid is used ? Support your answer with the help of a labelled circuit diagram.
Answer:
Permanent electromagnet is obtained if

1. direct current flows through the solenoid and
2. steel rod (a magnetic substance) is placed inside the solenoid.

In other words, a steel rod can be made a permanent electro-magnet if it is placed inside a solenoid carrying direct current as shown in figure.

Question 15.
AB is a current carrying conductor in the plane of the paper as shown in figure. What are the directions of magnetic fields produced by it at points P and Q ? Given, r₁ > r₂, where will the strength of the magnetic field be larger ?
(CBSE 2010, 2012)

Answer:
According to Right hand thumb rule, the direction of the mag¬netic field is into the plane of the paper at P and the direction of the magnetic field is out of the plane of the paper at Q.
The strength of the magnetic field due to a current carrying conductor decreases with increase in distance (i.e. B ∝ 1/r ).
Therefore, strength of the magnetic field will be larger at point Q than at point P.

Question 16.
A magnetic compass shows a deflection when placed near a current carrying wire. How will the deflection of the compass get affected if the current in the wire is increased ? Support your answer with a reason. (CBSE 2012)
Answer:
A magnetic compass is a tiny magnet. It gets deflected when placed in a magnetic field. When the current in the wire increases, then the magnetic field produced by the wire also increases (∴ B ∝ I). Hence, deflection of the compass increases.

Question 17.
It is established that an electric current through a metallic conductor produces a magnetic field around it. Is there a similar magnetic field produced around a thin beam of moving

1. alpha particles,
2. neutrons ? Justify your answer.
   (CBSE 2012)

Answer:

1. A thin beam of moving alpha particles constitute an electric current. Thus, beam of moving alpha particles behaves as a current carrying conductor. Hence, magnetic field is produced around the thin beam of moving alpha particles.
2. Neutrons are neutral particles i.e. they do not have any charge. Therefore, moving neutrons do not constitute an electric cur-rent. Hence, no magnetic field is produced around the thin beam of moving neutrons.

Question 18.
What does the direction of thumb indicate in the right-hand thumb rule. In what way this rule is different from Fleming’s left-hand rule ? (CBSE 2010,2012)
Answer:
In the right hand rule, the direction of thumb indicates the direction of flow of current in the straight conductor.
Right-hand thumb rule is used to determine the direction of the magnetic field produced by a current carrying straight conductor. However, Flemings left hand rule is used to determine the direction of the force experienced by a current carrying conductor placed in a uniform magnetic field.

Question 19.
Meena draws magnetic field lines of field close to the axis of a current carrying circular loop. As she moves away from the centre of the circular loop, she observes that the lines keep on diverging. How will you explain her observation ? (CBSE 2010)
Answer:
Magnetic field due to current carrying circular loop decreases as we move away from the centre of the loop. Diverging field lines represent weak magnetic field.

Question 20.
What does the divergence of magnetic field lines near the ends of a current carrying straight solenoid indicate ?
Answer:
Divergence of magnetic field lines means the magnetic field lines are far apart. Such field lines indicate weak magnetic field. There¬fore, divergence of magnetic field lines near the ends of the current carrying solenoid indicates that the magnetic field near the ends of the current carrying solenoid is weak and non-uniform.

Question 21.
Name four appliances wherein an electric motor, a rotating device that converts electrical energy to mechanical energy is used as an important component. In what respect motors are different from generators ?
Answer:
Appliances wherein an electric motor is used are

1. electric fan,
2. electric mixer,
3. washing machine and
4. a toy car.

Motor converts electrical energy into mechanical energy. How-ever, generator converts mechanical energy into electrical energy.

Question 22.
What is the role of two conducting stationary brushes in a simple electric motor ?
Answer:
These brushes act as the contacts between the commutator and the terminals of the battery.

Question 23.
What is the difference between direct current and an alternating current ? How many times does AC used in India change direction in one second ?
Answer:
Difference between Direct current and an Alternating current:

Since frequency is 50 Hz, so a.c. completes 50 cycles in 1 second. Therefore, it reverses its direction 100 times in one second.

Question 24.
What is the role of fuse, used in series with any electrical appli-ances ? Why should a fuse with defined rating not be replaced by one with a larger rating ?
Answer:
Electric fuse is a safety device. It protects the electrical appliance due to short circuiting and overloading in the electric circuit.
Fuse with defined rating means the maximum current that can flow’ through the fuse wire without melting it. As and when current exceeds this maximum value, the fuse melts and the circuit is switched off. If fuse with defined rating is replaced by one with a larger rating, then large current will flow through the circuit without melting the fuse. This large current may burn the electrical appliance connected in the circuit and the fuse will not act as a safety device.

Hope given NCERT Exemplar Solutions for Class 10 Science Chapter 13 Magnetic Effects of Electric Current 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 13 Magnetic Effects of Electric Current

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 13 Magnetic Effects of Electric Current

Question 1.
A fuse wire is a safety device to protect the electric circuit. Ashok used a fuse rated as 5 A in a circuit in which an electric heater of 2 kW was connected with the main supply of 220 V. The heater was not operating as the fuse wire melted on switching. Ashok was puzzled and he discussed the problem with his friend Ram. Ram suggeted him to use a fuse rated 10 A in the circuit. The problem of Ashok was solved as the heater was now working.
(i) What values are shown by Ram ?
(ii) How much current was flowing in the circuit with the fuse rated 10 A ?
Answer:
(i) Helpful, high degree of awareness.

More Resources

• Value Based Questions in Science for Class 10
• HOTS Questions for Class 10 Science
• NCERT Solutions for Class 10 Science
• NCERT Exemplar Solutions for Class 10 Science
• Previous Year Question Papers for CBSE Class 10 Science

Question 2.
Overloading in an electric circuit causes fire. Common people are unware of this fact. Akshil, an intelligent student told people of his locality about overloading. He told them to take various precautions to avoid overloading. What values are shown by Akshil ?
He is helpful and has high degree of awareness. Interested in educating people.

Question 3.
Students of a school ‘X’ went to a forest for a picnic. They went deep into the forest and started playing on a flat field in the forest. A stranger came there and asked for help. He had forgotten the direction of his village situated in south direction outside the forest. All the students except Sobit said that they had no idea about south direction. They asked stranger to find the south direction himself. However, Sobit asked him to wait for a moment. Sobit had a magnetic compass. He placed the magnetic compass on the ground and told the stranger about south direction.

1. How the magnetic compass determines the direction from the given place ?
2. What values are shown by Sobit ?
3. Is the behaviour of other students desirable ?

Answer:

1. When a magnetic compass is placed at a place, it always points towards north-south direction.
2. Sobit is helpful, caring and has a high degree of awareness.
3. The behaviour of other students is undesirable. They did not bother about the problem of the stranger.

Question 4.
Aayan was going to his home from his school. On his way, he heard that people in a house were crying and weeping. He went to the house to know the reason. He found that a boy is lying on a floor and people around him were crying and weeping. He came to know that boy suffered a severe shock, when he was working with electric iron. He asked people to stop crying and help him to take the boy to the nearby dispensary for Medical aid. The boy was rushed to the dispensary. Medical aid was given to him and his life was saved.
Answer the following questions based on above information.

1. Why the boy suffered severe shock ?
2. Comment on the values shown by Aayan.

Answer:

1. The boy might have touched the metallic casing of electric iron through which current was passing. Hence boy suffered a severe shock.
2. Aayan is helpful. He feels concerned about the welfare of others. He is quick in his actions and has high degree of general awareness.

Question 5.
What would you suggest to the people of your area regarding the safety measures in using electricity ?
Answer:

1. Use of electric fuses of proper rating,
2. Electricity wires should not be touched bare footed.
3. Electricity should be switched off during lightning and thunder,
4. Electric circuits should be properly earthed,
5. Avoid overloading i.e. electric appliances of high power rating should not be connected in a single socket or circuit.

Hope given Value Based Questions in Science for Class 10 Chapter 13 Magnetic Effects of Electric Current 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.