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A photographic plate is directly in forn...

A photographic plate is directly in fornt of as small diffused source in the shape of a circular disc. It takes 12 s to get a good exposure. If the source is rotated by `60^@` about one of its diameters, the time needed to get the same exposure will be

A

6s

B

12s

C

24s

D

48

Text Solution

Verified by Experts

The correct Answer is:
C
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