Question

A uniform (normal) magnetic field, B, bends the path of the most energetic photoelectrons, (emitted from a given photosensitive surface due to the action of monochromatic radiations of wave length λ) into a circle of radius r. The work function, W, for the given photosensitive surface, equals

Answer 1

Correct option : (3)

Explanation : 

Let W be the work function of the given photosensitive surface. The K.E. (K), of the most energetic emitted photoelectrons, is then given by

Now K = 1/2 mv². The radius, r, of the path into which these electrons get bent by a uniform (normal) magnetic field, is given by mv²/r = evB