Question

A charge of +2 micro-coulombs is moving at 20 m/s in the +x direction in a magnetic field of 0.02 T in the -z direction. The mass of the charge is 0.001 kg. What is the motion of this charge?

Answer 1

Since, force on a charge particle (q) moving with velocity V in an external magnetic field B given by F and calculated by,

F = q ( V * B) Here bold letters shows vector and * shows vector product.

F = q*V*B ( x * (-k) )

F = 2 * 10^(-6) * 20 * 0.02 (Y)

F = 0.08 * 10^(-5) (Y)

Since , the direction of force is in Y direction and because of it the charged particle will move in the circular path of radius let say R, continuously

To find the radius , we will have to use the concept of circular motion , and F will play role of centripetal force.

using concept of centripetal force , we can write

F (centripetal) = (m * V^2) / R

R = ( 0.001 * 400 ) / ( 0.08 * 10^(-5) )

R = 5 * (10^5) m

So, the particle will move in the circle of Radius 5*10^5 m in X-Y plane.