Question

The work function of the following metals is given : Na = 2.75 eV, K = 2.3 eV, Mo = 4.17 eV and Ni = 5.15 eV. Which of these metals will not cause photoelectric emission for radiation of wavelength 3300 from a laser source placed 1 m away from these metals ? What happens if the laser source is brought nearer and placed 50 cm away ?

Answer 1

In case of Na and K Eo < E

.'. photoelectric emission takes place but in the case of M0 and Ni band gap is more no. photoelectric emission.

When the laser is brought the closer intensity of incident radiation increases

.'. the photoelectric current increase, for Na and K effect in case of M0 and Ni.