09. Heat Engine, Carnot’s Cycle and Refrigeration (COP)
Thermodynamics

148670 A reversible engine converts one-sixth of the heat supplied into work. When the temperature of the sink is reduced by $62^{\circ} \mathrm{C}$, the efficiency of the engine is doubled. The temperatures of the sources and sink are

1 $99^{\circ} \mathrm{C}, 37^{\circ} \mathrm{C}$
2 $80^{\circ} \mathrm{C}, 37^{\circ} \mathrm{C}$
3 $95^{\circ} \mathrm{C}, 37^{\circ} \mathrm{C}$
4 $90^{\circ} \mathrm{C}, 37^{\circ} \mathrm{C}$
Thermodynamics

148671 Two cylinders A and B fitted with pistons contain equal number of moles of an ideal monoatomic gas at $400 \mathrm{~K}$. The piston of $A$ is free to move while that of $B$ is held fixed. Same amount of heat energy is given to the gas in each cylinder. If the rise in temperature of the gas in $A$ is $42 \mathrm{~K}$, the rise in temperature of the gas in $B$ is

1 $21 \mathrm{~K}$
2 $35 \mathrm{~K}$
3 $42 \mathrm{~K}$
4 $70 \mathrm{~K}$
Thermodynamics

148672 On tripling the absolute temperature of the source, the efficiency of a Carnot's heat engine becomes double that of the initial efficiency. Then the initial efficiency of the engine is

1 $20 \%$
2 $50 \%$
3 $60 \%$
4 $40 \%$
Thermodynamics

148673 In the cyclic process shown in the $\mathrm{P}-\mathrm{V}$ diagram calculate the work done.

1 $\pi\left(\frac{\mathrm{V}_{2}-\mathrm{V}_{1}}{2}\right)^{2}$
2 $\pi\left(\frac{\mathrm{P}_{2}-\mathrm{P}_{1}}{2}\right)^{2}$
3 $\frac{\pi}{4}\left(\mathrm{P}_{2}-\mathrm{P}_{1}\right)\left(\mathrm{V}_{2}-\mathrm{V}_{1}\right)$
4 $\pi\left(\mathrm{P}_{2} \mathrm{~V}_{2}-\mathrm{P}_{1} \mathrm{~V}_{1}\right)$
Thermodynamics

148670 A reversible engine converts one-sixth of the heat supplied into work. When the temperature of the sink is reduced by $62^{\circ} \mathrm{C}$, the efficiency of the engine is doubled. The temperatures of the sources and sink are

1 $99^{\circ} \mathrm{C}, 37^{\circ} \mathrm{C}$
2 $80^{\circ} \mathrm{C}, 37^{\circ} \mathrm{C}$
3 $95^{\circ} \mathrm{C}, 37^{\circ} \mathrm{C}$
4 $90^{\circ} \mathrm{C}, 37^{\circ} \mathrm{C}$
Thermodynamics

148671 Two cylinders A and B fitted with pistons contain equal number of moles of an ideal monoatomic gas at $400 \mathrm{~K}$. The piston of $A$ is free to move while that of $B$ is held fixed. Same amount of heat energy is given to the gas in each cylinder. If the rise in temperature of the gas in $A$ is $42 \mathrm{~K}$, the rise in temperature of the gas in $B$ is

1 $21 \mathrm{~K}$
2 $35 \mathrm{~K}$
3 $42 \mathrm{~K}$
4 $70 \mathrm{~K}$
Thermodynamics

148672 On tripling the absolute temperature of the source, the efficiency of a Carnot's heat engine becomes double that of the initial efficiency. Then the initial efficiency of the engine is

1 $20 \%$
2 $50 \%$
3 $60 \%$
4 $40 \%$
Thermodynamics

148673 In the cyclic process shown in the $\mathrm{P}-\mathrm{V}$ diagram calculate the work done.

1 $\pi\left(\frac{\mathrm{V}_{2}-\mathrm{V}_{1}}{2}\right)^{2}$
2 $\pi\left(\frac{\mathrm{P}_{2}-\mathrm{P}_{1}}{2}\right)^{2}$
3 $\frac{\pi}{4}\left(\mathrm{P}_{2}-\mathrm{P}_{1}\right)\left(\mathrm{V}_{2}-\mathrm{V}_{1}\right)$
4 $\pi\left(\mathrm{P}_{2} \mathrm{~V}_{2}-\mathrm{P}_{1} \mathrm{~V}_{1}\right)$
Thermodynamics

148670 A reversible engine converts one-sixth of the heat supplied into work. When the temperature of the sink is reduced by $62^{\circ} \mathrm{C}$, the efficiency of the engine is doubled. The temperatures of the sources and sink are

1 $99^{\circ} \mathrm{C}, 37^{\circ} \mathrm{C}$
2 $80^{\circ} \mathrm{C}, 37^{\circ} \mathrm{C}$
3 $95^{\circ} \mathrm{C}, 37^{\circ} \mathrm{C}$
4 $90^{\circ} \mathrm{C}, 37^{\circ} \mathrm{C}$
Thermodynamics

148671 Two cylinders A and B fitted with pistons contain equal number of moles of an ideal monoatomic gas at $400 \mathrm{~K}$. The piston of $A$ is free to move while that of $B$ is held fixed. Same amount of heat energy is given to the gas in each cylinder. If the rise in temperature of the gas in $A$ is $42 \mathrm{~K}$, the rise in temperature of the gas in $B$ is

1 $21 \mathrm{~K}$
2 $35 \mathrm{~K}$
3 $42 \mathrm{~K}$
4 $70 \mathrm{~K}$
Thermodynamics

148672 On tripling the absolute temperature of the source, the efficiency of a Carnot's heat engine becomes double that of the initial efficiency. Then the initial efficiency of the engine is

1 $20 \%$
2 $50 \%$
3 $60 \%$
4 $40 \%$
Thermodynamics

148673 In the cyclic process shown in the $\mathrm{P}-\mathrm{V}$ diagram calculate the work done.

1 $\pi\left(\frac{\mathrm{V}_{2}-\mathrm{V}_{1}}{2}\right)^{2}$
2 $\pi\left(\frac{\mathrm{P}_{2}-\mathrm{P}_{1}}{2}\right)^{2}$
3 $\frac{\pi}{4}\left(\mathrm{P}_{2}-\mathrm{P}_{1}\right)\left(\mathrm{V}_{2}-\mathrm{V}_{1}\right)$
4 $\pi\left(\mathrm{P}_{2} \mathrm{~V}_{2}-\mathrm{P}_{1} \mathrm{~V}_{1}\right)$
Thermodynamics

148670 A reversible engine converts one-sixth of the heat supplied into work. When the temperature of the sink is reduced by $62^{\circ} \mathrm{C}$, the efficiency of the engine is doubled. The temperatures of the sources and sink are

1 $99^{\circ} \mathrm{C}, 37^{\circ} \mathrm{C}$
2 $80^{\circ} \mathrm{C}, 37^{\circ} \mathrm{C}$
3 $95^{\circ} \mathrm{C}, 37^{\circ} \mathrm{C}$
4 $90^{\circ} \mathrm{C}, 37^{\circ} \mathrm{C}$
Thermodynamics

148671 Two cylinders A and B fitted with pistons contain equal number of moles of an ideal monoatomic gas at $400 \mathrm{~K}$. The piston of $A$ is free to move while that of $B$ is held fixed. Same amount of heat energy is given to the gas in each cylinder. If the rise in temperature of the gas in $A$ is $42 \mathrm{~K}$, the rise in temperature of the gas in $B$ is

1 $21 \mathrm{~K}$
2 $35 \mathrm{~K}$
3 $42 \mathrm{~K}$
4 $70 \mathrm{~K}$
Thermodynamics

148672 On tripling the absolute temperature of the source, the efficiency of a Carnot's heat engine becomes double that of the initial efficiency. Then the initial efficiency of the engine is

1 $20 \%$
2 $50 \%$
3 $60 \%$
4 $40 \%$
Thermodynamics

148673 In the cyclic process shown in the $\mathrm{P}-\mathrm{V}$ diagram calculate the work done.

1 $\pi\left(\frac{\mathrm{V}_{2}-\mathrm{V}_{1}}{2}\right)^{2}$
2 $\pi\left(\frac{\mathrm{P}_{2}-\mathrm{P}_{1}}{2}\right)^{2}$
3 $\frac{\pi}{4}\left(\mathrm{P}_{2}-\mathrm{P}_{1}\right)\left(\mathrm{V}_{2}-\mathrm{V}_{1}\right)$
4 $\pi\left(\mathrm{P}_{2} \mathrm{~V}_{2}-\mathrm{P}_{1} \mathrm{~V}_{1}\right)$