#### A photoelectric surface is illuminated successively by monochromatic light of wavelength and  . If the maximum kinetic energy of the emitted photoelectrons in the second case is 3 times that in the first case, the work function of the surface of the material is :(h = Planck's constant, c = speed of light) Option 1) Option 2) Option 3) Option 4)

As discussed in

Conservation of energy -

- wherein

Let work function be

According to the question,

Or,

Or,

Or,

Option 1)

This option is incorrect.

Option 2)

This option is incorrect.

Option 3)

This option is incorrect.

Option 4)

This option is correct.