Physics Electricity and Magnetism 2

Question 1

Two parallel plates are separated by 0.01 m with a voltage of 100 V across them. What is the electric field strength between the plates?

Accepted Answer

10,000 V/m

Answer

Electric field E = V/d = 100 V / 0.01 m = 10,000 V/m.

Question 2

A magnetic field exerts no force on a charged particle when the particle moves:

Accepted Answer

Parallel to the field

Answer

The magnetic force F = qv×B is zero when velocity is parallel (or anti-parallel) to B, since sin(0°) = 0.

Question 3

Which law relates the line integral of the magnetic field around a closed loop to the current enclosed by that loop?

Accepted Answer

Ampere's Law

Answer

Ampere's Law states ∮B·dl = μ₀I_enclosed.

Question 4

A capacitor fully charged to 12 V is connected to a resistor. After one time constant τ, the voltage across the capacitor is approximately:

Accepted Answer

4.4 V

Answer

After one time constant, V = V₀·e⁻¹ ≈ 12 × 0.368 ≈ 4.4 V.

Question 5

The energy stored in an inductor carrying current I with inductance L is:

Accepted Answer

½LI²

Answer

The energy stored in an inductor is U = ½LI².

Physics Practice Test