Chapter 11, Problem 28P

An electron in a TV CRT moves with a speed of $6.0\times {10}^7$ m/s, in a direction perpendicular to Earth's field, which has a strength of $5.0\times {10}^{-5}$ T. (a) What strength electric field must be applied perpendicular to the Earth’s field to make the election moves in a straight line? (b) If this is done between plates separated by 1.00 cm, what is the voltage applied? (Note that TVs are usually surrounded by a ferromagnetic material to shield against external magnetic fields and avoid the need for such a collection,)