Q - Write the expression for the force acting on a charged particle of charge (q) moving with a velocity (v) in the presence of magnetic field (B). show that in presence of this force :

(i) the Kinetic Energy of particle does not change.

(ii) Instantaneous power is zero.

Force experienced by the charged particle is given by:

F = q (v X B)

Work done by this force is zero. As the direction of force is along the direction of displacement. 

=> Since there is no work done, that means the kinetic energy remains the same. 

Power = F.v 

 =q(v X B).v

 = 0 

The instantaneous power is zero.