Question

When a certain metallic surface is illuminated with monochromatic light of wavelength \( \lambda \), the stopping potential for photoelectric current is \( V_0 \). When the same surface is illuminated with a light of wavelength \( 2\lambda \), the stopping potential is \( V_1 \). The threshold wavelength for this surface to photoelectric effect is

• A. \( \lambda_0 \)
• B. \( 6\lambda \)
• C. \( \frac{4\lambda}{3} \)
• D. \( \frac{3\lambda}{4} \)

Hint:

In photoelectric effect, the stopping potential is inversely proportional to the wavelength of the incident light.

Answer 1

The Correct Option is A

Step 1: Using the photoelectric equation.
The stopping potential is related to the wavelength of the incident light. When the wavelength doubles, the stopping potential also changes accordingly. We calculate the threshold wavelength for the given condition.

Step 2: Conclusion.
The threshold wavelength is \( \lambda_0 \), corresponding to option (1).