A-Level H2 Physics 4

Question 1

What is the first law of thermodynamics?

Accepted Answer

ΔU = Q + W, where ΔU is change in internal energy, Q is heat added, and W is work done on the system

Answer

First law of thermodynamics: ΔU = Q + W. The change in internal energy equals heat added to the system plus work done on the system. It is the law of conservation of energy for thermodynamic systems.

Question 2

What is the condition for stationary waves to form?

Accepted Answer

Two coherent waves of the same frequency and amplitude travelling in opposite directions

Answer

Stationary (standing) waves form when two waves of the same frequency, amplitude, and wavelength travel in opposite directions and superpose. They have fixed nodes and antinodes.

Question 3

A proton is accelerated from rest through a potential difference of 500V. What kinetic energy does it gain? (e = 1.6×10⁻¹⁹ C)

Accepted Answer

8×10⁻¹⁷ J

Answer

KE gained = qV = 1.6×10⁻¹⁹ × 500 = 8×10⁻¹⁷ J.

Question 4

What is the difference between progressive and stationary waves?

Accepted Answer

Progressive waves transfer energy; stationary waves do not transfer energy in the direction of the wave

Answer

Progressive waves transfer energy from one point to another. Stationary waves have nodes and antinodes — energy is stored between nodes but not transferred in the direction of the wave.

Question 5

What is the formula for gravitational field strength?

Accepted Answer

g = GM/r²

Answer

Gravitational field strength g = GM/r², where G is the gravitational constant, M is the mass of the body causing the field, and r is the distance from its centre.

GCE A-Level Practice Test

GCE A-Level Practice Test

A-Level H2 Physics 4