Question

When UV light of wavelength 300 nm is incident on the metal surface having work function 2.13 eV, electron emission takes place. The stopping potential is : (Given hc = 1240 eV nm)

• A. 4 V
• B. 4.1 V
• C. 2 V
• D. 1.5 V

Answer 1

Answer: (C)

2 V

Answer 2

The energy of the incident photon is given by:
$\frac{hc}{\lambda} = eV_s + \phi$
Substitute the given values:
$\frac{1240}{300} \, \text{eV} - 2.13 \, \text{eV} = eV_s$
$4.13 \, \text{eV} - 2.13 \, \text{eV} = eV_s$
$V_s = 2 \, \text{V}$