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 1 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 is
Answer: Option 3
Explanation: As the diameter on lens remain same, both the lens will collect the same amount of light. Therefore, the intensity of the light will remain the same as a result the photoeletric current will also remain the same.