Heat Engines and Refrigerators

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,

What is the sequence of expansion in the process of Carnot cycle?

In carnot's engine at the end of the cycle, the temperature of the working substance 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 work done by the gas of thermal expansion in the Carnot cycle is

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

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

 A cyclic heat engine does 50kJ of work per cycle. If efficiency of engine is 75%, the heat rejected per cycle will be

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?

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

An ideal heat engine exhausting heat at $77°\mathrm{C}$ is to have a $30\%$ efficiency. It must take the heat at:

An ideal refrigerator has a freezer at a temperature of $-13°\mathrm{C}$. The coefficient of performance of the refrigerator is $5.$ The temperature of the air (to which heat is rejected) will be:

A Carnot engine absorbs $750 \mathrm{J}$ of heat energy from a reservoir at $137 \mathrm{℃}$ and rejects $500 \mathrm{J}$ of heat during each cycle, then the temperature of sink is

An ideal gas heat engine operates in a carnot cycle between $227°\mathrm{C}$ and $127°\mathrm{C}$. It absorbs $6 \mathrm{kcal}$ at the higher temperature. The amount of heat (in $\mathrm{kcal}$) converted into work is equal to 

A carnot refrigeration cycle absorbs heat at $270 \mathrm{K}$ and rejects heat at $300 \mathrm{K}.$ If the cycle is absorbing $1260 \mathrm{kJ}/\min$ at $270 \mathrm{K},$ then work required per second is:

A heat engine is operating between $500 \mathrm{K}$ to $300 \mathrm{K}$. If the engine absorbs $100 \mathrm{J}$ heat, then which of the following is impossible amount of heat rejected by this heat engine.

Two Carnot's engines $A$ and $B$ have the same efficiency. $A$ receives heat from a source at $800 \mathrm{K}$ and rejects to a sink at  $\text{'}x\text{'}$ kelvin. $B$ receives heat rejected by $A$ and rejects to another sink at $300 \mathrm{K}$. The temperature  $\text{'}x\text{'}$ is nearly _____.

An engine has an efficiency of $\frac{1}{6}$. When the temperature of sink is reduced by $62°\mathrm{C}$, its efficiency is doubled. The temperatures of source and sink are,

The efficiency of a Carnot engine with low-temperature reservoir at $7°\mathrm{C}$ is $50\%.$ To have the efficiency of $70\%$ by how many degrees should the temperature of the high-temperature reservoir be increased?