Define the following in photoelectric effect phenomenon
(a) (i) work function
(ii) Stopping potential (cut-off potential)
(b) calculate energy of photon of wavelenght `3.31 Å`

Explanation

(a) Work function: The minimum energy required to make an electron free from the metal is called work function. It is constant for a metal and denote by `phi` or `W`. It is the minimum for cesium. It is relatively less or alkali metals.
(ii) Stopping potential: Minimum magnitude of negative potential of anode with respect to cathode for which current is zero is called stopping potential. This is also known as cuttof voltage. This voltage is independent of intensity.
b. `E=(12420)/(3.31)eV= 3.752 KeV`