Tag: solar power plant

Questions Related to solar power plant

Increasing the surface area of a solar cell 

  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.


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.

  1. True

  2. False


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 :

  1. Red

  2. Yellow

  3. Black

  4. Green


Correct Option: C
Explanation:

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

Two identical immersion heaters are to be used to heat water, in a large container. Which one of the following arrangement would heat the water faster :
Give reasons for your answer.

  1. Connecting the heaters in series with the main supply,

  2. Connecting the heaters in parallel with the main supply,

  3. Connecting the heaters in series and parallel with the main supply,

  4. None of the above


Correct Option: A

Relation between constant volume specific heat $(C _v)$ and degree of freedom $(f)$ for a gas is ($R$ is gas constant) 

  1. $C _v=\dfrac{f}{2} R$

  2. $C _v=fR$

  3. $C _v=\dfrac{f}{R}$

  4. $C _v=\dfrac{R}{f}$


Correct Option: A
Explanation:

The internal energy of 1 mole of an ideal gas at temperature $T$ , having $f$ degrees of freedom is given by ,

          $U=N _{A}\times(1/2)fk _{B}T=(1/2)fRT$  ......................eq1
where $N _{A}=$Avogadro's number
           $k _{B}=$ Boltzmann's constant
from first law of thermodynamics ,
           $dU=dQ-dW$  ............eq2
At constant volume , $dV=0$ 
hence  $dW=PdV=0$
eq2 becomes , $dU=dQ$
but       $dQ=C _{V}dT$  (for 1 mole of gas)
therefore $dU=C _{V}dT$
or            $C _{V}=dU/dT$
putting the value of $U$ in this equation, we get
                $C _{V}=\frac{d(1/2)fRT}{dT}=\frac{f}{2}R$

Temperature of a gas is $20^o$C and pressure is changed from $1.01\times 10^5$ Pa to $1.165\times 10^5$ Pa. If volume is decreased isothermally by $10\%$. Bulk modulus of gas is?

  1. $1.55\times 10^5$

  2. $0.155\times 10^5$

  3. $1.4\times 10^5$

  4. $1.01\times 10^5$


Correct Option: A
Explanation:
$B=-V\dfrac{\Delta P}{\Delta V}$
$=V _0\dfrac{(1.165-1.01)\times 10^5}{0.1\ V}$
$=1.55\times 10^5$

The room heater can maintain only ${16^0}C$ in the room when the temperature outside is -${20^0}C$. It is not warm and comfortable, that is why the electric stove with power of 1 kw is also plugged in.Together these two devices maintain the room temperature of ${22^0}C$. Determine the thermal  power of the heater.

  1. 3kW

  2. 4 kW

  3. 5kW

  4. 6kW


Correct Option: C

The device which directly converts solar energy into electric energy is called

  1. solar cooker

  2. solar furnace

  3. solar cell

  4. none of these


Correct Option: C
Explanation:

A solar cell takes solar energy directly from the sunlight and converts it into electrical energy.

In a mechanically isolated system, which interaction is allowed?

  1. Mass flow

  2. Work

  3. Heat flow

  4. None of these


Correct Option: C
Explanation:

A mechanically isolated system is that , which cannot do work on environment and there is no exchange of mass between system and environment but exchange of heat is allowed between system and environment .