Consider an electron traveling in the negative y-direction at a constant speed o
ID: 1429105 • Letter: C
Question
Consider an electron traveling in the negative y-direction at a constant speed of 6.210e+06 m/s. The electron enters into a region of a constant magnetic field. The magnetic field is in a direction that is perpendicular to the direction of the electron's motion. If the Lorentz force acting on the electron is found to be 5.273e-16 N, and the Lorentz force is in the negative z-direction,
(a) What is the magnitude (or the absolute value) of the magnetic field?
(b) What is the direction of the magnetic field?
1.negative x-direction
2.negative y-direction
3.positive z-direction
4.positive y-direction
5.negative z-direction
6.positive x-direction
Explanation / Answer
given
v = 6.21*10^6 m/s (towards -y axis)
F = 5.273*10^-16 N (towards -z axis)
we know, charge of electron, |q| = 1.6*10^-19 C
a) magnetic force acting on moving electron,
F = q*v*B*sin(90)
==> B = F/(q*v)
= 5.273*10^-16/(1.6*10^-19(6.21*10^6)
= 5.3*10^-4 T
b) 6.positive x-direction
using the rlation, F = q*(v cross B)