When a monochromatic point source of light is at a distance of `0.2` m from a photoelectric cell, the cut off voltage and the saturation current are respectively `0.6V` and `18.0 mA` if the same source is placed `0.6 m` away from the photoelectric cell , then

Options

A. the stopping potential will be `0.2 V`
B. the stopping potential will be `0.6 V`
C. the saturation current will be `6 mA`
D. the saturation current will be `18 mA`

Answer

B

Explanation

Cutt - off voltage is independent of intensity and hence remains the same . Since distance becomes `3 times` , so intensity `(I)` becomes `I//9`. Hence photo current also decreases by this factoe , i.e., becomes `18//9 = 2 mA`.