Question

An electron is moving at 7.4 x 10^5 m/s perpendicular to a magnetic field. It experiences a force of -2.0 x 10^-13 N. What is the magnetic field strength?

Answer 1

Answer: B = 1.69 T

Explanation: Given that the

Electron velocity V = 7.4 × 10^5 m/s

Force F = - 2 × 10^-13 N

Charge q =  -1.602 x 10-19 C.

We are given the charge, its velocity, and the magnetic field strength and direction. We can thus use the equation F = qvB sin θ .

Since the electron is moving perpendicular to a magnetic field,

sin θ = sin 90 = 1, therefore

- 2 × 10^-13 = - 1.602×10^-19 × 7.4×10^5B

B = -2×10^-13/1.2×10^-13

B = 1.68708T

B = 1.69 T