CHAPTER 24.2 NOTESForces caused by magnetic fields

Galvanometer

What is it? A device used to measure very small currents (like those produced by a magnetic field)

The Formula

F = Bqv

F = B = q = v =

F = Bqv

F = force (N)B = magnetic field strength (Teslas)

q = the charge on a particle ©v = velocity (m/s)

Remember,

If the particle you are dealing with is an electron, its’ charge will always be

1.6 x 10-19 C

We used this in chapter 20…

Example problems

1. A beam of electrons moving at a speed of 3 x 109 m/s passes thru a magnetic field that has a strength of .0005T. What force acts on the electrons in the magnetic field?

2. Electrons in a cathode ray tube are moving at 6 x 104 m/s and pass thru a magnetic field with a force of 0.45 N. What is the strength of the magnetic field?

Answers:

1. 2.4 X 10-13N

2. 4.68 x 1013 T

Today’s assignment

p. 772 #’s 6-10, 14-16

Your Electricity and Magnetism test is Wednesday!

Review Chapter 22-24 notesdefinitions, units, domains, Field lines,Right -Hand rules

Know how to use formulas to problem solveVoltage drops, current, power, magnetic field, equivalent resistance, etc