Question

A and B are two metals with threshold frequencies \( 1.8 \times 10^{14} \, \text{Hz} \) and \( 2.2 \times 10^{14} \, \text{Hz} \). Two identical photons of energy \( 0.825 \, \text{eV} \) each are incident on them. Then photoelectrons are emitted by (Take \( h = 6.6 \times 10^{-34} \, \text{J.s} \)):

• A. A alone
• B. B alone
• C. Neither A nor B
• D. Both A and B

Hint:

For photoelectric emission, the energy of the incident photons must be greater than the work function of the material.

Answer 1

The Correct Option is B

Using the photoelectric effect equation \( E_{\text{photon}} = h \nu - W \), where \( \nu \) is the frequency, we can calculate whether photoelectrons are emitted. Only metal B has sufficient energy to emit photoelectrons.

Step 2: Conclusion.
Photoelectrons are emitted by metal B alone, corresponding to option (b).