Question

A charged particle is moving without deflection in a space region where an elec- tric field E = 3.5x102V/m and a magnetic field B = 0.25T act in perpendicular directions.

Calculate the speed of the particle.

Answer 1

$F_1=qE,$

$F_2=qvB,$

$F_1=F_2,$

$v=\frac EB,$

$v=\frac{3.5\cdot 10^2}{0.25}=14~\frac{km}{s}.$