Carnot Cycle

Q.

In which of the following processes, the net work done is Zero?

1. Cyclic

2. Adiabatic

3. Isochoric

4. Free Expansion

Q. In Carnot's cycle, the process immediately followed by isothermal expansion is

1. Isothermal compresion
2. Adiabatic compression
3. Adiabatic expansion
4. Free expansion

Q.

State whether in actual machines, the output energy is greater or lesser than input energy. Give reason.

Q.

The efficiency of the Otto cycle is given by which of these expressions?Where r = compression ratio.

1. $1-\frac{1}{r^{\gamma -1}}$

2. $1-\frac{1}{{\gamma }^{r-1}}$

3. $\frac{1}{r}$

4. $\frac{1}{\gamma }$

Q. A carnot engine operates between two reservoirs of temperature 900 $K$ and 300 $K$. The engine performs 1200 $J$ of work per cycle. The heat energy in ($J$) delivered by the engine to the low temperature reservoir, in a cycle, is

Q. An ideal Carnot engine whose efficiency is 40% receives heat at 500 K. If its efficiency were 50%, then in take temperature for same exhaust temperature would be

1. 700 K
2. 900 K
3. 800 K
4. 600 K

Q. A Carnot engine, having an efficiency of $\eta =1/10$ as heat engine, is used as a refrigerator. If the work done on the system is $10J$, the amount of energy absorbed from the reservoir at lower temperature is

1. $90J$
2. $99J$
3. $100J$
4. $1J$

Q. Consider the same Carnot engine that operates between the temperatures $T_H$ 850 K and $T_L$300 K. The engine performs 1200 J of work each cycle, which takes 0.25 s. What is the average power of this engine?

1. 4.8 kw
2. 4.8 w
3. 5.6 kw
4. 5.6 w

Q. What is the temperature of source in Carnot cycle of 10% efficiency when heat exhausts at 270 K?

1. 400 K
2. 500 K
3. 300 K
4. 600 K

Q. In which process in Carnot's cycle, heat $\left(Q_2\right)$ is released to the sink?

1. Reversible adiabatic expansion
2. Reversible adiabatic compression
3. Reversible isothermal expansion.
4. Reversible isothermal compression

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

1. Efficiency of Carnot engine cannot be made larger than $50\%$
2. $1200$ K
3. $750$ K
4. $600$ K

Q. Two Carnot engines $A$ and $B$ are operated in succession. The first one, $A$ receives heat from a source at $T_1=800\text{K}$ and rejects to a sink at $T_2\text{K}$. The second engine $B$ receives heat rejected by the first engine and rejects to another sink at $T_3=300\text{K}$. Find the value of $T_2$ if
(i) the work outputs of the two engines are equal.
(ii) the efficiencies of the two engines are equal.

Q. The efficiency of a Carnot engine working between 800 K and 500 K is

1. 0.4
2. 0.625
3. 0.375
4. 0.5

Q.

Figure below represents a Carnot engine that works between temperatures $T_1$ 400 K and $T_2$ 150 K and drives aCarnot refrigerator that works between temperatures $T_3$ 325 K and $T_4$ 225 K.What is the ratio $\frac{Q3}{Q1}$?

1. $\frac{104}{85}$

2. $\frac{104}{95}$

3. $\frac{85}{104}$

4. $\frac{95}{104}$

Q. An engine does 41, 000 J of useful work. If it sinks 9, 000 J of energy in the form of heat to its cold reservoir, find the heat energy supplied to the engine's hot reservoir?

1. 41000 J
2. 9000 J
3. 32000 J
4. 50000 J

Q.

A device containing an ideal gas executes the cycle shown. This is a :

1. heat engine
2. refrigerator
3. Neither because the net work done by/on the device is zero

Q. The efficiency of a Carnot engine working between 800 K and 500 K is

1. 0.4
2. 0.625
3. 0.375
4. 0.5

Q.

In one cycle of the engine, the net change in the entropy of both reservoirs (hot and cold together) is:

1. zero
2. greater than or equal to zero
3. less than zero
4. depends on the type of engine

Q.

An ideal gas is taken through the process ABCDA as shown. Which process(s) is/are isobaric?

1. AB and CD
2. BC and DA
3. All processes
4. None of above

Q. Imagine a Carnot engine that operates between the temperatures $T_H$ 850 K and $T_L$ 300 K. The engine performs 1200 J of work each cycle, which takes 0.25 s. What is the efficiency of this engine?

1. $\frac{11}{19}$

2. $\frac{11}{17}$

3. $\frac{8}{19}$

4. $\frac{6}{17}$