physics
posted by Sandhya on .
What is the force on an electron moving at v = 2.5*10^5 m/s away from a long wire,3mm from the electron, carrying a 12 A current? Give the magnitude & direction of the force.
I calculated mag induction using
B = u0I/2(pi)*a and
force on the electron using
F = Bqv where q is the electron charged(assumed)
The force acts opposite to the direction of electron motion & towards the centre
Am I right?

The force is perpendicular to the B vector and perpendicular to the V vector.

You are in your car traveling at a constant velocity of 94 km/h. A car that you know to be 3.5 m long is passing you. If it takes the other car 1.8 s to pass you (from the time your front bumpers are even until the other car's rear bumper passes your front bumper), what is the passing car's velocity relative to Earth?