Radiations of frequency `10^(15)Hz` is incident on three photosenstive surfaces. A,B and C. Following observations are recorded,
(a) Surface A. No photoemission occurs.
(b) Surface B. Photoemission occurs but the photoelectrons have zero kinetic energy.
(c) Surface C. Photoemission occurs and photoelectrons have some KE.
Based on Einstein's photoelectric equation, expalain the three observations.

Radiation of frequency 10^(15)Hz is incident separately on two photosensitive surfaces P and Q. The following observations were made: (i) surface P: Photoemission occurs but the photoelectrons have zero kinetic energy (ii) surface Q: Photoemission occurs and electrons have non-zero kinetic energy. Which of these two has higher work function? If the frequency of incident light is reduced, what will happen to photoelectron emission in the two cases?

Radiation of frequency 10^(15)Hz is incident on two photosensitive surface P and Q . There is no photoemission from surface P . Photoemission occurs from Q but photoelectrons have zero kinetic energy. Explain these observation and find the value of work function for surface Q .

Radiation of frequency 10^(15)Hz is incident on two photosensitive surface P and Q. There is no photosensitive from surface P. Photoemission occurs from surface Q but photoelectrons have zero kinetic energy. Explain these observations and find the value of work function for surface Q.

(i) State two important features of Einstein's photoelectric equation. (ii) Radiation of frequency 10^(15)Hz is incident on two photosenstive surface P and Q. There is no photoemission from surface P. Photoemission occurs from Q but photoelectrons have zero kinetic energy. Explain these observation and find the value of work function for surface Q.

Two photosensitive X and Y are exposed to radiations of frequency 10^(12)Hz . Comment on threshold frequency of each surface if photoelectrons emitted from surface X have zero kinetic energy and that from surface Y have some positive kinetic energy .

Radiations of frequencies 8xx10^(15) Hz and 5xx10^(15) Hz are incident one after the another on the same photosensitive surface. If is found that the kinetic energies of the photo electrons emitted from the surface are in the ratio of 2:1 . What is the threshold frequency for the surface ?