Answer
$v=3750\frac{m}{s}$
Work Step by Step
The electron's speed is equal to the ratio of the electric field and magnetic Field:
$v=\frac{E}{B}$
We plug in the known values of $E,B$ to obtain:
$v=\frac{1.50\times10^3}{0.400}$
$v=3750\frac{m}{s}$
