In photoelectric experiment energy of 2.48 eV irradiates a photo sensitive material. The stopping potential was measured to be 0.5 V. Work function of the photo sensitive material is :

Solution

Physics sir · 4 steps

Photon energy pays the work function first; whatever is left shows up as eV₀ of kinetic energy.

1. Energy balance. Each photon gives all its energy to one electron. Part of it, the work function φ, is used to pull the electron out of the surface, and the rest becomes the electron's maximum kinetic energy.

   hν = φ + eV₀

2. Stopping potential. The stopping potential V₀ = 0.5 V just halts the fastest electrons, so their kinetic energy is eV₀ = 0.5 eV.
3. Put in numbers. φ = hν - eV₀ = 2.48 eV - 0.5 eV = 1.98 eV.
4. So. The work function of the material is 1.98 eV, option (a).

The idea to keep. In eV units, a stopping potential of V₀ volts means a maximum kinetic energy of V₀ eV. Then φ = hν - eV₀ is a one-line subtraction.

Answer from the NTA final answer key. Solution by PrepWiser.