When monochromatic source is kept at distance of 0.2 m from photocell,cutoff voltage obtained is 0.6 V and saturation current is 18 mA.Noe if source is kept at distance of 0.6 m…….

Options

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

Answer

B

Explanation

Stopping potential is independent of intensity.Hence will remain 0.6.V
When distance is charged to 0.6 m (3 times)
`1prop (1)/(d^(2))`
`therefore (I_(2))/(I_(1))=(d_(1)^(2))/(d_(2)^(2))`
`therefore (I_(2))/(I)=((0.2)^(2))/((0.6)^(2))=(1)/(9)`
`therefore I_(2)=(I)/(9)=(18)/(9)=2mA`