When a charged particle moves in a magnetic field, does its KE always remain constant?

Explanation

A charged particle moving in a magnetic field of constant intensity does not gain kinetic energy. This is because the force is `vec F = q (vec V xx vec B)` and work done, `W = vec f.vec s` or in 1 second,
`vec F. vec V = a(vec V xx vec B ) vec V =0` because of property of scalar triple product.