NEET Physics Question - Modern Physics - Photoelectric Effects and deBroglie Equation

Assertion (A): The stopping potential increases, when frequency of incident rays are increased.

Reason (R): Stopping potential is directly proportional to the frequency of incident radiation.

Both (A) & (R) are true and the (R) is the correct explanation of the (A)

Both (A) & (R) are true but the (R) is not the correct explanation of the (A)

(A) is true but (R) is false

Both (A) and (R) are false

Solution:

Concept: Einstein's photoelectric equation.
Formula: \(eV_s = hf - \phi_0\) or \(V_s = \frac{h}{e}f - \frac{\phi_0}{e}\) where \(f\) is frequency and \(\phi_0\) is work function.
Solution: From the formula, as frequency \(f\) increases, the stopping potential \(V_s\) also increases. So (A) is true. However, \(V_s\) is linearly dependent on \(f\) with an intercept of \(-\frac{\phi_0}{e}\) (unless \(\phi_0 = 0\)), not directly proportional. So (R) is false.

Rankers Physics

Photoelectric Effect: Stopping Potential vs. Frequency

Solution:

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