question_answer

An image of the sun is formed by a lens of 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 is                                                     [Manipal MEE 1995]

A)            \[\frac{I}{2}\]                       

B)            I

C)            2I   

D)            4I