Physics 2 Homework Question

Question

Consider an electron near the Earth’s equator. In which direction does it tend to deflect if its velocity is (a) directed downward? (b) directed northward? (c) directed southeastward?

Answer 1

Use the RHR. The magnetic field is pointed in the (geographic) North direction - so align your middle finger in that direction. Direct your index finger in the direction of qv, where q is negative here, so the directions in (a), (b), and (c) are opposite to what is shown for the electron. Then your thumb would be directed in the direction of force, hence the deflection.