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Consider a system of N atoms of an ideal gas of type A at temperature T and volume V. It is kept in diffusive contact with another system of N atoms of another ideal gas of type B at the same temperature T and volume V. Once the combined system reaches equilibrium.
Select one:
The correct answer is: entropy of final system is equal to the sum of individual entropies
A heat pump uses 300 J of work to remove 400 J of heat from the lowtemperature reservoir. How much heat is delivered to a higher temperature reservoir?
W = 300 J
Q_{C }= 400 J
Q_{H = }W + Q_{C}
Q_{H = }300 J + 400 J
Q_{H =} 700 J
Heat delivered to the higher temperature reservoir is 700 J.
For the thermodynamics process shown in the figure, corresponding TS diagram is
Select one:
The T–S diagram of two cycles for the operation of an engine are shown in figure below.
The numerical values of the parameters T_{1} , T_{2} , S_{1} and S_{2} in the two figures are the same, then which cycle has greater efficiency?
Select one:
Efficiency
For curve
Available energy per cycle is
Q_{1} – Q_{2} = Area of curve (ABC)
Q_{1} = Total area of curve (ABED)
⇒ Area of curve is same for both figures, but total area is more for Fig. 1.
Hence, second figure has greater efficiency.
The correct answer is: Second
An electric current of 3A flows through a resistance of 10 ohm. It is being cooled by running water and is kept at temperature 300K, change in entropy per second of the resistance :
Select one:
There is no change in the entropy of the resistance because there is no change in the state of wire.
The correct answer is: No change
Out of three Carnot engines, operating between reservoir temperature of (a) 400 and 500 K (b) 600 and 800 K (c) 400 and 600 K, which has the greater thermal efficiency?
A reversible engine cyclic is shown in the following T–S diagram. The efficiency of the engine is :
Select one:
In given figure, available energy per cycle is
= T_{1}S_{1}
and Q_{1} = 3T_{1}S_{1}
efficiency
The correct answer is: 1/3
An engine absorbs heat at temperature of 1000 K and rejects heat at 600 K. If the engine operates at maximum possible efficiency, the amount of work performed by the engine for 200 J heat input is
Select one:
An amount of heat Q is transferred from a heat reservoir at temperature T_{A} to another heat reservoir at temperature T_{B}. What is the change in the entropy Δs of the combined system?
Select one:
Conventionally, heat given to the system is taken to be positive and heat extracted from the system is taken to be negative.
When heat is changed in the system entropy changed by an amount,
∴ For A
Similarly for B,
ΔS = ΔS_{A} + ΔS_{B}
The correct answer is:
The difference in entropy between a state of volume V_{i} and a state of volume V_{f} (temperature and number of molecules remaining constant) is equal to :
Select one:
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