Ray Optics Question 3
Question 3 - 2024 (27 Jan Shift 1)
A convex lens of focal length $40 cm$ forms an image of an extended source of light on a photoelectric cell. A current $I$ is produced. The lens is replaced by another convex lens having the same diameter but focal length $20 cm$. The photoelectric current now is :
(1) $\frac{1}{2}$
(2) 4 I
(3) 2 I
(4) I
Show Answer
Answer: (4)
Solution:
As amount of energy incident on cell is same so current will remain same.
