Tag: generation of electricity

Questions Related to generation of electricity

Food gets cooked faster in a pressure cooker because ___________________.

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  1. Water starts boiling at a higher temperature due to high pressure

  2. Water boils only at 100 °C but the heat content is higher at high pressure

  3. Water boils only at 100 °C but the heat content is higher at low pressure

  4. Convection currents are set inside the cooker

Show answer
Correct Option: A

A solar cell converts ________ (sound / light) energy to_______ (light /  electrical) energy. Fill the blanks. 

physics solar equipment production of electricity from solar energy solar power alternate sources of energy solar power plant solar energy and its applications renewable and non-renewable resources renewable and non-renewable sources of energy generation of electricity

  1. Light, electrical

  2. Sound , light

  3. electrical, light

  4. None of the above

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Correct Option: A

Photo voltaic cells use _________ to produce electricity.

physics solar equipment production of electricity from solar energy solar power alternate sources of energy solar power plant solar energy and its applications renewable and non-renewable resources renewable and non-renewable sources of energy generation of electricity

  1. water stored by a dam

  2. heat energy of coal or petroleum

  3. wind energy

  4. solar energy

Show answer
Correct Option: D

The efficiency of a solar cell is 20% and its surface area is $4  {cm}^{2}$. Find the electrical energy generated in one second, by 3000 cells, connected in a solar panel, if $640  J$ of solar energy is incident on one meter square area, in one second.

physics solar equipment production of electricity from solar energy solar power alternate sources of energy solar power plant solar energy and its applications renewable and non-renewable resources renewable and non-renewable sources of energy generation of electricity

  1. 183.6 J

  2. 153.6 J

  3. 193.6 J

  4. 123.6 J

Show answer
Correct Option: B
Explanation:

The total surface area of solar cells on which solar energy is falling = area of each cell $\times$ number of cells $= 4 \times 3000 {cm}^{2} = 1.2  {m}^{2}$
The solar energy falling on 3000 cells 
${Q} _{1} = 1.2 \times 640  J = 768  J$
The energy converted into electric energy $= \displaystyle\frac{20}{100} \times 768 = 153.6  J$
The electric energy generated in one second is $153.6  J$

The temperature in a spherical reflector type solar cooker is raised to above $500 ^oC$ by :

physics solar equipment production of electricity from solar energy solar power alternate sources of energy solar power plant solar energy and its applications renewable and non-renewable resources renewable and non-renewable sources of energy generation of electricity

  1. concentrating energy at one point by using a concave reflector

  2. proper insulation of the cooker

  3. concentrating energy at one point by using a convex reflector

  4. Both (A) and (B)

Show answer
Correct Option: D

State whether true or false :
We can also prepare food on a cloudy day through solar cooker.

physics solar equipment production of electricity from solar energy solar power alternate sources of energy solar power plant solar energy and its applications renewable and non-renewable resources renewable and non-renewable sources of energy generation of electricity

  1. True

  2. False

Show answer
Correct Option: B
Explanation:

No On cloudy day solar cooker did not get sufficient amount of sunlight to produce heat energy for cooking.

State whether true or false :
We can adjust parabolic solar cooker in such a way so that the mirror moves with the sun in order to face the sun always. 

physics solar equipment production of electricity from solar energy solar power alternate sources of energy solar power plant solar energy and its applications renewable and non-renewable resources renewable and non-renewable sources of energy generation of electricity

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

If we did not adjust the parabolic mirror in solar cooker according the  movement of sun then all ray of sunlight cannot converge at one point .hence  with time we will get lesser amount of heat energy.

Increasing the surface area of a solar cell 

physics solar equipment production of electricity from solar energy solar power alternate sources of energy solar power plant solar energy and its applications renewable and non-renewable resources renewable and non-renewable sources of energy generation of electricity

  1. increases the current and the power output.

  2. increases the voltage and the power output.

  3. decreases the current output but increases the power output.

  4. has no effect.

Show answer
Correct Option: A
Explanation:

Output of solar cell occurs at a constant voltage. Using a group of solar cells in the solar panel increases the amount of current produced. Also, as area is increased more solar energy is captured and more electrical energy is produced.

State whether true or false :
Solar Energy doesn't cause any pollution.

physics solar equipment production of electricity from solar energy solar power alternate sources of energy solar power plant solar energy and its applications renewable and non-renewable resources renewable and non-renewable sources of energy generation of electricity

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

 Solar energy systems/power plants do not produce air pollution, water poullution, or greenhouse gases. ... However, some toxic materials and chemicals are used to make the photovoltaic (PV) cells that convert sunlight into electricity.

In order to absorb more heat, the outer surface of copper tube of solar water heater is coloured with :

physics solar equipment production of electricity from solar energy solar power alternate sources of energy solar power plant solar energy and its applications renewable and non-renewable resources renewable and non-renewable sources of energy generation of electricity

  1. Red

  2. Yellow

  3. Black

  4. Green

Show answer
Correct Option: C
Explanation:

Among all colour black is the best absorber for heat  so outer surface of copper tube is coloured with black.