A photoelectric surface is illuminated successively by monochromatic light of wavelength $\lambda$ and $\frac{\lambda}{2}$ . If the maximum kinetic energy of the emitted photoelectrons in the seconds case is 3 times that in the first case, the work function of the surface of the material is : <br> (h = Planck’s constant, c = speed of light)

Question

( A ) $\frac{hc}{\lambda}$
( B ) $\frac{hc}{3\lambda}$
( C ) $\frac{2hc}{\lambda}$
( D ) $\frac{hc}{2\lambda}$