Practice Magnetic Field in Physics

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

Quick Recap

A region around a magnet or moving charge where magnetic forces act. Measured in tesla (T).

Moving charges create a swirling force field around them. This field can push on other moving charges or magnets.

Example 1

medium
A proton (q = 1.6 \times 10^{-19} \text{ C}) moves at 3 \times 10^6 \text{ m/s} perpendicular to a magnetic field of 0.5 \text{ T}. What force does it experience?

Example 2

hard
A wire carrying 5 \text{ A} of current is 0.3 \text{ m} long and placed perpendicular to a 0.2 \text{ T} magnetic field. What force acts on the wire?

Example 3

medium
An electron moves at 2 \times 10^7 \text{ m/s} at 30° to a 0.1 \text{ T} magnetic field. What is the magnetic force on the electron? (|q_e| = 1.6 \times 10^{-19} \text{ C})

Example 4

hard
A proton (q = 1.6 \times 10^{-19} \text{ C}, m = 1.67 \times 10^{-27} \text{ kg}) enters a uniform magnetic field of 0.2 \text{ T} at 90° with a speed of 5 \times 10^6 \text{ m/s}. Calculate: (a) the magnetic force, (b) the radius of its circular path.
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