Light of wavelength A which is less than threshold wavelength is incident on a photosensitive material. If incident wavelength is decreased so that emitted photoelectrons are moving with same velocity, then stopping potential will

Options

A. increase
B. decrease
C. be zero
D. become exactly half

Answer

A

Explanation

For photoemission , `lambda lt lambda_(0)` (threshold wavelength).
If the wavelength is decreased further, then the frequency `[v=C/lambda]`, of the incident light will increase and the K.E. of the emitted photoelectrons will increase or their speed will increase.
In order to boring them back to the original speed, stopping potential should be increased.