NSAA NSAA Physics - Thermal Physics and Thermodynamics 2

Question 1

In an adiabatic process, which of the following is true?

Accepted Answer

No heat is exchanged with the surroundings

Answer

An adiabatic process is defined by Q = 0, meaning no heat is transferred between the system and its surroundings.

Question 2

A Carnot engine operates between a hot reservoir at T_H = 600 K and a cold reservoir at T_C = 300 K. What is its efficiency?

Accepted Answer

50%

Answer

Carnot efficiency η = 1 − T_C/T_H = 1 − 300/600 = 0.50 = 50%.

Question 3

Which statement correctly expresses the second law of thermodynamics?

Accepted Answer

The entropy of an isolated system tends to increase in irreversible processes

Answer

The second law states that natural processes in isolated systems proceed in the direction of increasing entropy.

Question 4

The specific latent heat of vaporization of a substance is the energy required to:

Accepted Answer

Convert 1 kg of liquid to gas at constant temperature

Answer

Latent heat of vaporization is the energy per unit mass needed to change phase from liquid to gas at constant temperature and pressure.

Question 5

According to the kinetic theory of gases, pressure is caused by:

Accepted Answer

Collisions of gas molecules with the container walls

Answer

Gas pressure arises from the rate of momentum transfer when molecules collide elastically with the container walls.

NSAA - Natural Sciences Admissions Assessment Practice Test