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The exposure time of a camera lens at t...

The exposure time of a camera lens at the `(f)/(2.8)` setting is `(1)/(200) ` second. The correct time of exposure at `(f)/(5.6)` is

A

0.4 s

B

0.02 s

C

0.002 s

D

0.04 s

Text Solution

Verified by Experts

The correct Answer is:
B
Time of exposure `prop ("f number" )^(2)`
`rArr (t_(2))/(t_(1)) = ((5.6)/(2.8))^(2) = 4 rArr t_(2) = 4t_(1) = 4 xx (1)/(200)`
`" " = (1)/(50) sec = 0.02 ` sec.
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