When a surface is irradiated with light of wavelength `4950 Å`, a photocurrent appears which vanishes if a retarding potential greater than 0.6 volt is applied across the phototube. When a second source of light is used, it is found that the critical potential is changed to 1.1 volt.
if the photoelectrons (after emission form the source) are subjected to a magnetic field of 10 tesla, the two retarding potentials would

Answer

A, B, C, D

Explanation

`0.6 = (12375)/(4950) -W …(i)
`1.1 =12375)/(lambda) - W …..(ii)`
Solving above two equations, we get
W = 1.9 ev
and `lambda = 4125 Å`