Question

Magnetic Forces:

A proton in a magnetic field travels in a clockwise circle on the page with radius 20 cm. What direction is the magnetic field? What is the radius if the magnetic strength is doubled?

Please show all work. Thank you in advance!

Answer 1

We know that the magnetic field, magnetic force and velocity are perpendicular to each other.

B filed must be perpendicular to the plane of the velocity. So it should be out of the page or into the page. for confirmed response, the direction of magnetoc force is also needed here.

We know that, the magnetic force bends the charge from a normal path to the curved path. and centripital force is provided by magnetic force.

F(magnetic) = F(centripital)

q v B = m v^2/R

R = mv/Bq

if the magnetic field will be doubled the radius will be halved.

R' = 1/2 x 20 = 10 cm

R' = 10 cm