Light is incident on the cathode of a photocell and the stopping voltages are measured for light of two different wavelengths, are given below.

a. Determine the work function of the metal of the cathode in eV.
b. Find the value of the universal constant `(hc)/(e )`.
c. Define stopping potential and work function.
d. Can you suggest a mathematical relation between kinetic energy and stopping potential?

Explanation

a. `(hc)/(lambda)=phi_(0)+eV_(0)" "` Ans. 2.3 eV
b. `1.24xx10^(-6)`
c. If the applied potential is negative, the photoelectric current decreases and becomes zero for a certain negative value. This value of potential is called stopping potential or cut-off potential. The minimum amount of work required to emit electrons from a metal surface is called work function.
d. `eV_(0)=K_("max")`