The exposure time of a camera lens at the $\frac{f}{2.8}$ setting is $\frac{1}{200}$ second. The correct time of exposure at $\frac{f}{5.6}$ is

Question

Dr. Abubacker · Accepted Answer

(b) Time of exposure $\propto (f.\ number)^{2} \Rightarrow \frac{t_{2}}{t_{1}} = \left( \frac{5.6}{2.8} ight)^{2} = 4$
$t_{2} = 4t_{1} = 4 	imes \frac{1}{200} = \frac{1}{50}sec = 0.02\ sec$

Q. The exposure time of a camera lens at the $\frac{f}{2.8}$ setting is $\frac{1}{200}$ second. The correct time of exposure at $\frac{f}{5.6}$ is

Explanation

Reviewed by Dr. Abubacker

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