Question

A charged particle is moving on circular path with velocity v in a uniform magnetic field B, if the velocity of the charged particle is doubled and strength of magnetic field is halved, then radius becomes
(a) 8 times
(b) 4 times
(c) 2 times
(d) 16 times

Answer 1

Radius of charged particle, r = mv/qB

So, new radius acc to ques , r' = m. 2v/ qB/2 = 4 r

Correct Option is (b) 4 times