Question

A particle of charge Q and mass m passes through a region of width d, which has a uniform magnetic field B. Its initial velocity v is perpendicular to B. If d is slightly greater than (mv/BQ), the particle will get deflected through an angle 

(a) π/4 

(b) π/3 

(c) π/2 

(d) π 

Answer 1

Correct Answer is: (d) π 

mv = BQr or r = mv/BQ .

Here, d  mv/BQ or d  r.

The particle will just complete half of one rotation inside the field.