Physics Thermodynamics 2

Question 1

Which thermodynamic process occurs at constant pressure?

Accepted Answer

Isobaric

Answer

An isobaric process occurs at constant pressure, so work done equals P×ΔV.

Question 2

A Carnot engine operates between 600 K and 300 K. What is its maximum efficiency?

Accepted Answer

50%

Answer

Carnot efficiency = 1 − T_cold/T_hot = 1 − 300/600 = 0.50 = 50%.

Question 3

When an ideal gas expands adiabatically, its temperature:

Accepted Answer

Decreases

Answer

In an adiabatic expansion, the gas does work on surroundings with no heat exchange, so internal energy and temperature decrease.

Question 4

The efficiency of a real heat engine compared to a Carnot engine operating between the same temperatures is always:

Accepted Answer

Less

Answer

Real engines have irreversibilities (friction, heat leaks), making their efficiency always less than the ideal Carnot efficiency.

Question 5

Which quantity is a state function in thermodynamics?

Accepted Answer

Enthalpy

Answer

Enthalpy (H = U + PV) is a state function; work and heat are path-dependent process quantities.

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