12th Grade > Physics
WORK POWER AND ENERGY MCQs
Work And Energy, Sources Of Energy, Electric Potential Energy Potential And Dipoles
Total Questions : 109
| Page 9 of 11 pages
Answer: Option B. -> large amount of potential energy is converted into kinetic energy.
:
B
In a hydroelectric power plant, more electrical power can begenerated if water falls from a greater height because more the height of water, more is the potential energy stored in it. So, the larger amount of potential energy is converted into kineticenergy. More is the kinetic energy, faster it willrotate the turbineand hence moreelectricity is generated.
:
B
In a hydroelectric power plant, more electrical power can begenerated if water falls from a greater height because more the height of water, more is the potential energy stored in it. So, the larger amount of potential energy is converted into kineticenergy. More is the kinetic energy, faster it willrotate the turbineand hence moreelectricity is generated.
Answer: Option A. -> Sources of energy which are naturally replenished
:
A
Sources which are replaced naturally and can be usedagain is known as a renewable source of energy. Sun, wind, biomass are some of the examples of renewable sources of energy.
:
A
Sources which are replaced naturally and can be usedagain is known as a renewable source of energy. Sun, wind, biomass are some of the examples of renewable sources of energy.
Question 83. A satellite gets unstable in its orbit and starts to fall towards Earth and also starts heating. If the satellite had a potential energy of 1000 J initially and by the time it reaches Earth's surface, it attains a kinetic energy of 500 J. Then, how much energy is spent in the form of heat?
Answer: Option C. -> 500 J
:
C
Given, initialpotential energy = 1000 J
Final kinetic energy = 500 J
Here, potential energy is converted to kinetic energy and heat.
So,potential energy = Kinetic energy + Heat
→ 1000 = 500 + Heat
∴ Heat= 500 J
:
C
Given, initialpotential energy = 1000 J
Final kinetic energy = 500 J
Here, potential energy is converted to kinetic energy and heat.
So,potential energy = Kinetic energy + Heat
→ 1000 = 500 + Heat
∴ Heat= 500 J
Answer: Option B. -> Burning of fossil fuels releases oxides of carbon, nitrogen and sulphur in the atmosphere.
:
B
Acid rain happens becausethe burningof fossil fuels releasesoxides of carbon, nitrogen andsulfurin the atmosphere.These substances can rise veryhighinto the atmosphere, where theymix andreact with water, oxygen, andotherchemicals to form more acidic pollutants, known as acid rain.
:
B
Acid rain happens becausethe burningof fossil fuels releasesoxides of carbon, nitrogen andsulfurin the atmosphere.These substances can rise veryhighinto the atmosphere, where theymix andreact with water, oxygen, andotherchemicals to form more acidic pollutants, known as acid rain.
Answer: Option B. -> Temperature difference at different levels in the ocean.
:
B
Ocean thermal energy is generated due to the difference in temperature of water at the surface of the ocean and temperature at deeper levels of the ocean. This energycomes indirectly from the sun as theheat energy from the sun is creating the difference in temperature.
:
B
Ocean thermal energy is generated due to the difference in temperature of water at the surface of the ocean and temperature at deeper levels of the ocean. This energycomes indirectly from the sun as theheat energy from the sun is creating the difference in temperature.
Answer: Option B. -> They need regular maintenance due to moving parts within.
:
B
Solar panels consistof solar cells which are connected with each other by silver wiring. A solar paneldoes not have any moving part within it. They are widely used in artificial satellites but their domestic use is limited due to high cost and requirement of large open area.
:
B
Solar panels consistof solar cells which are connected with each other by silver wiring. A solar paneldoes not have any moving part within it. They are widely used in artificial satellites but their domestic use is limited due to high cost and requirement of large open area.
Answer: Option D. -> Soil
:
D
Biomass is waste material from plants or animals that is not used for food or feed such as wood, cow dung, etc. Soil cannot be used as a biofuel rather all the biofuels convert into soil after they are consumed.
:
D
Biomass is waste material from plants or animals that is not used for food or feed such as wood, cow dung, etc. Soil cannot be used as a biofuel rather all the biofuels convert into soil after they are consumed.
Question 88. There are two mutual perpendicular forces acting on an object. One force acts in the direction of motion of the object and other is perpendicular to the motion. During this interval, the kinetic energy of the body changes from 25 J to 100 J. The work done by the force acting perpendicular to the direction of the object is:
Answer: Option B. -> 0 J
:
B
Theforce acting perpendicular to the direction of motion produces no displacement and so the work done by this force is zero.
In the above question, the kinetic energy would increase only due to the force acting in the direction of motion or velocity of the object. The force acting perpendicular to the direction of motion has no contribution to the increase in kinetic energy and hence it does no work.
:
B
Theforce acting perpendicular to the direction of motion produces no displacement and so the work done by this force is zero.
In the above question, the kinetic energy would increase only due to the force acting in the direction of motion or velocity of the object. The force acting perpendicular to the direction of motion has no contribution to the increase in kinetic energy and hence it does no work.
Answer: Option B. -> 10 W
:
B
Change in kinetic energy =1200 J
Time taken= 2 min = 120 s
The potential energy of the waterfall is utilised to move the turbine blades and the change in kinetic energy would be equal to the work done which is equal to 1200 J. Power is defined as the work done per unit time
Power = workdonetime=1200120=10W.
:
B
Change in kinetic energy =1200 J
Time taken= 2 min = 120 s
The potential energy of the waterfall is utilised to move the turbine blades and the change in kinetic energy would be equal to the work done which is equal to 1200 J. Power is defined as the work done per unit time
Power = workdonetime=1200120=10W.
Answer: Option B. -> Chemical - Kinetic - Heat
:
B
The man got chemical energy by the intake of glucose which then transformed into kinetic energy and as it slides on a rough floor, it would eventually come to rest due to friction, in which heat will be released.
:
B
The man got chemical energy by the intake of glucose which then transformed into kinetic energy and as it slides on a rough floor, it would eventually come to rest due to friction, in which heat will be released.
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