Lesson: Motion of Charged Particles in Uniform Magnetic Fields Physics • 9th Grade

In this lesson, we will learn how to determine the magnetic forces on charged particles in uniform magnetic fields and the motion produced by these forces.

Lesson Worksheet

Q1:

A particle has a charge of 160 µC. The particle enters a region containing a 420 mT uniform magnetic field, moving in the -direction at 360 m/s and in the -direction at 250 m/s, as shown in the diagram.

Calculate the magnitude of the force that acts on the particle at the point where it enters the field. Answer to two significant figures.

At what counterclockwise angle from the positive -direction in the -plane does the force act? Answer to the nearest degree.

Q2:

An electron is traveling at 3,250 m/s when it enters a 1.25 T magnetic field that is directed perpendicularly to the direction of the electron’s motion. Find the displacement of the electron from the point it enters the magnetic field to the point where its velocity is at a right angle to the direction of its velocity when it entered the field. Use the value C for the electron charge and the value kg for the electron mass. Give your answer in scientific notation to two decimal places.

Q3:

An electron is traveling at 5,700 m/s when it enters a 3.5 mT uniform magnetic field that is directed perpendicularly to the direction of the electron’s motion. Find the radius of the electron’s path. Use the value C for the electron’s charge and the value kg for the electron’s mass. Answer in scientific notation to one decimal place.