1. The problem statement, all variables and given/known data
A certain solenoid(50cm long with 2000 loops) carries a current of 0.70A and is in vacuum. An electron is shot at an angle of 10deg to the solenoid axis from a point on the axis.
Find the speed of the electron if it is just to miss hitting the inside of the 1.6cm diameter solenoid?
2. Relevant equations
B=unI
r=mv/qB
v=qrB/m
3. The attempt at a solution
B=(12.5*10^7)(2000/0.5m)(0.7)/sin10=0.020T
v=0.20T * 0.008m*1.6*10^19C=2.8*10^7m/s<<<the manual says the velocity is 1.4*10^7 don't understand why it's half of what I got. Please help.
