Question

If the distance of 100 W lamp is increased from a photocell, the saturation current in the photocell varies with the distance \( d \) as?

• A. \( i \propto d^2 \)
• B. \( i \propto \frac{1}{d^2} \)
• C. \( i \propto \frac{1}{d} \)
• D. \( i \propto \frac{1}{d^3} \)

Hint:

The intensity of light decreases with the square of the distance, so the current in the photocell varies as \( \frac{1}{d^2} \).

Answer 1

The Correct Option is B

The saturation current in a photocell is inversely proportional to the square of the distance between the light source and the photocell, based on the inverse square law for light intensity.