Question

what direction is the magnetic force and electric force going.

aA straight line. b. A circle. c. An ellipse. d. A parabola. Part II: Solve 4 out of 5 problems 21 points each, show all work to get credit . An electron moves through a region of crossed electric and magnetic fields. he electric field E-2500 V/m and is directed downwards. The magnetic field B 1.25 T and is directed to the left. (a). Specify the directions of electric and magnetic forces on the electron if it moves into the page (b). For what velocity r of the electron will the electric force exacly cancel the magnetic force?

Answer 1

The electric force of the electron is given by

$F_e=-eE$

Electric force will be vertically upwards.

Magnetic force is

$F_b=-e(v \times B)$

The direction of the magnetic force will be vertically downwards for the two forces to cancel each other.

$\\eE=evB \\ v=\frac{E}{B}$

$v=\frac{250}{1.25}=200 \: m/s$