Practice Magnetic Force in Physics
Use these practice problems to test your method after reviewing the concept explanation and worked examples.
Quick Recap
The force exerted on a moving charge or current-carrying conductor by a magnetic field.
A moving charge in a magnetic field feels a sideways push — perpendicular to both its motion and the field. It's like a cross-wind deflecting a moving ball.
Example 1
easyA proton (q = 1.6 \times 10^{-19} \text{ C}) moves at 5 \times 10^6 \text{ m/s} perpendicular to a 0.3 \text{ T} magnetic field. What is the magnetic force on the proton?
Example 2
mediumA wire carrying 8 \text{ A} is 0.5 \text{ m} long and placed at 60° to a 0.4 \text{ T} magnetic field. What force acts on the wire?
Example 3
mediumA proton (q = 1.6 \times 10^{-19} \text{ C}) moves at 3 \times 10^6 \text{ m/s} perpendicular to a 0.5 \text{ T} magnetic field. Find the magnetic force.
Example 4
mediumAn electron (q = 1.6 \times 10^{-19} \text{ C}, m = 9.11 \times 10^{-31} \text{ kg}) moves at 2 \times 10^7 \text{ m/s} perpendicular to a 0.01 \text{ T} field. What is the radius of its circular path?
Example 5
hardTwo parallel wires 0.1 \text{ m} apart each carry 10 \text{ A} in the same direction. What is the force per meter between them? Is it attractive or repulsive? Use \mu_0 = 4\pi \times 10^{-7} \text{ T m/A}.