AP Physics Physics: Thermodynamics & Modern Physics 2

Question 1

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

Accepted Answer

50%

Answer

25%

Answer

75%

Answer

100%

Question 2

Which thermodynamic process occurs at constant pressure?

Accepted Answer

Isobaric

Answer

Isochoric

Answer

Isothermal

Answer

Adiabatic

Question 3

In the photoelectric effect, increasing the intensity of light while keeping frequency constant will:

Accepted Answer

Increase the number of ejected electrons per second

Answer

Increase the maximum kinetic energy of ejected electrons

Answer

Increase the threshold frequency

Answer

Decrease the work function of the metal

Question 4

What does the area under a P-V diagram curve represent?

Accepted Answer

Work done by or on the gas

Answer

Change in internal energy

Answer

Heat transferred

Answer

Change in entropy

Question 5

An electron transitions from the n=3 to n=1 energy level in a hydrogen atom. This transition produces:

Accepted Answer

An emitted photon in the ultraviolet range

Answer

An absorbed photon in the infrared range

Answer

An emitted photon in the visible range

Answer

An absorbed photon in the visible range

Question 6

A radioactive isotope has a half-life of 10 years. What fraction of the original sample remains after 30 years?

Accepted Answer

1/8

Answer

1/2

Answer

1/4

Answer

1/16

Question 7

Which statement best describes the Second Law of Thermodynamics?

Accepted Answer

The entropy of an isolated system tends to increase over time

Answer

Energy is always conserved in any process

Answer

Heat always flows from cold to hot objects

Answer

The internal energy of an ideal gas depends only on pressure