1. The problem statement, all variables and given/known data If I shoot an electron from the back of a TV at a screen towards the front at .5c (e= speed of light) What magnetic field must be in the coils around the cathode ray tube (picture tube) if the electron would have made a circle radius 30m if it hadn't hit the screen and made it glow. (your TV show) 2. Relevant equations r= (mv)/qB 3. The attempt at a solution Using the equation rearranged to solve for B: B=mv/qr mass of an electron = 9.1 x 10^-31 charge of an electron = 1.602 x 10^-19 .5c=....well it's half of the spd of light so I assume : 1.5 x 10^8 since the spd of light is 3x10^8 if I remember correctly. and radius = 30m so: B= (9.1x10^-31)(1.5x10^8)/(1.602x10^-19)(30) B= .026? Could someone check if I did this correctly, did I forget something?