Heat Engines and Refrigerators

A Carnot engine operates between a source and a sink. The efficiency of the engine is $40\%$ and the temperature of the $sink$ is $27°\mathrm{C}$. If the efficiency is to be increased to $50\%$ then the temperature of the source must the increased by

The temperature of the sink of a Carnot engine is $250 \mathrm{K}$. In order to increase the efficiency of the Carnot engine from $25\%$ to $50\%$, the temperature of the sink should be increased by

A diatomic ideal gas is used in a carnot engine as the working substance. If during the adiabatic expansion part of the cycle, the volume of the gas increases from $V$ to $32 \mathrm{V}$, the efficiency of the engine is,

Even Carnot engine cannot give $100\%$ efficiency because we cannot

A Carnot engine works between constant temperature $T_1$ and $T_2$ of source and sink, respectively. For efficiency to be greatest

The efficiency of all reversible heat engines operating between the same heat reservoirs is :

A Carnot engine whose efficiency is $40\%$ takes in heat from source maintained at a temperature of $500 \mathrm{K}$. It is desired to have an engine of efficiency $60\%$. Then, the intake temperature for the same exhaust (sink) temperature must be

A Carnot engine having an efficiency $1 / 5$ as a heat engine, is used as a refrigerator. If the work done on the system is $50 \mathrm{J}$, the amount of energy absorbed from the reservoir at lower temperature is

Three designs are proposed for an engine which is to operate between $500 \mathrm{K}$ and $300 \mathrm{K}$. Design A claims to produce $150 \mathrm{J}$ of work per $1000 \mathrm{J}$ of heat input, design B $400 \mathrm{J}$ of work per $1000 \mathrm{J}$ and design C $300 \mathrm{J}$ of work per $1000 \mathrm{J}$. Which of the designs would you choose?

Three Carnot engines operate in series between a heat source at temperature $T_1$ and heat sink at a temperature $T_4.$ There are two other reservoirs at temperatures $T_2$ and $T_3.$ The three engines are equally efficient if (given that $\_\_\_\_\_\_\_\_\_\_\_$$\left.T_1>T_2>T_3>T_4\right)$

The efficiency of Carnot heat engine _____

calculate the work done on the gas in carnot cycle during compression.

Isothermal compression in Carnot cycle happened at _____.

The correct sequence of the processes taking place in a carnot cycle is

The third process is isothermal compression.

A Carnot engine whose low-temperature reservoir is at $350 \mathrm{K}$ has an efficiency of $50\%$ . It is desired to increase this to $60\%$ . If the temperature of the low-temperature reservoir remains constant, then the temperature of the high-temperature reservoir must be increased by how many degrees?

Consider a reversible engine of efficiency $\frac{1}{6}$ . When the temperature of the sink is reduced by $62{ }^{\mathrm{o}}\mathrm{C}$ , its efficiency gets doubled. The temperature of the source and sink respectively are

When temperture ${\mathrm{T}}_1$ of heat reservoir increases by ${200}^{\mathrm{o}}\mathrm{C}$, the efficiency of the engine is nearly equal to __, if the temperatures $T_1$ and $T_2$ of heat reservoirs in an ideal Carnot engine are ${1800}^{\mathrm{o}}\mathrm{C}$ and ${600}^{\mathrm{o}}\mathrm{C}$ respectively. 

A refrigerator is to maintain the eatables, kept inside it, at $9°\mathrm{C}$. The coefficient of performance of the refrigerator, if the room temperature is $36°\mathrm{C}$, is

The efficiency of the Carnot engine is $50\%$ and the temperature of the sink is $500 \mathrm{K}$. If temperature of the source is kept constant and its efficiency is raised to $60\%$, then the required temperature of the sink will be