Question

A photon of energy 8 eV is incident on a metal surface of work function 3.75 eV. The stopping potential of the metal is

• A. \(3.25\text{ V}\)
• B. \(3.5\text{ V}\)
• C. \(4.15\text{ V}\)
• D. \(4.25\text{ V}\)

Hint:

Use Einstein's photoelectric equation: stopping potential in volts equals photon energy minus work function in eV.

Answer 1

The Correct Option is D

Step 1: Formula-first approach
$V_0=\dfrac{h\nu-\phi}{e}$, which equals the difference of the two energies in eV.

Step 2: Substitute
$V_0=8-3.75$.

Step 3: Compare the options
The difference is 4.25, which matches only one option; the others are off by a small amount.

Final Answer:
The stopping potential works out to 4.25 V. \[ \boxed{\text{(D) }4.25\text{ V}} \]