An image of the sun is formed by a lens, of the focal length of 30 cm, on the metal surface of a photoelectric cell and a photoelectric current I is produced. The lens forming the image is then replaced by another of the same diameter but of focal length 15 cm. The photoelectric current in this case isA. `I//2`B. `2I`C. `I`D. `4 I`

An image of the sun is formed by a lens, of the focal length of 30 cm,

1.	An image of the sun is formed by a lens, of the focal length of 30 cm, on the metal surface of a photoelectric cell and a photoelectric current I is produced. The lens forming the image is then replaced by another of the same diameter but of focal length 15 cm. The photoelectric current in this case isA. `I//2`B. `2I`C. `I`D. `4 I`
Answer» Correct Answer - C The current `I` is proportional to light energy falling on the lens per second with is same in the two cases. Hence same `I`.

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