Question

If velocity ofan electron is $(2i+3j)m{s}^{-1}$ and it enters
in the magnetic field of 4kT, then

• A. it will move in the direction of the magnetic field
• B. it will move in the opposite direction to the magnetic
  field
• C. direction of its velocity will change
• D. its speed will change

Answer 1

Answer: (C)

When a charged particle is projected perpendicular to a
magnetic field its path is circular in a plane perpendicular to
the field and the speed and KE of the particle remain constant
while velocity changes only in direction.