Question

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 :

• A. 0.5 eV
• B. 1.68 eV
• C. 2.48 eV
• D. 1.98 eV

Answer 1

Answer: (D)

1.98 eV

Answer 2

The energy relation for the photoelectric effect is:

$eV_s = h\nu - \phi$

where $eV_s$ is the stopping potential energy, $h\nu$ is the energy of incident photons, and $\phi$ is the work function.

Given: $h\nu = 2.48 \, \text{eV}, \, V_s = 0.5 \, \text{V}.$

$0.5 = 2.48 - \phi$

$\phi = 2.48 - 0.5 = 1.98 \, \text{eV}.$

The work function of the material is $\phi = 1.98 \, \text{eV}.$