Question

A photosensitive metallic surface has work function,
hv. If photons of energy 2hv, fall on this surface,
the electrons come out with a maximum velocity of
4 x 106 m/s. When the photon energy is increased
to 5hve, then maximum velocity of photoelectrons
will be​

Answer 1

Explanation:

When photons of frequency, 2ν0 are incident then the Einstein equation is 2mv12=2hν0−hν0

or 2mv12=hν0   ...........(1)

When 5ν0 is incident the Einstein equation becomes 

2mV22=5hν0−hν0=4hν0   .......(2)

Dividing equation-2 by equation-1 we get v22=4v12 or v2=2v1=2×4×106m/s=8×106m/s

Option D is correct.