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The power of the composite lens made of two thin lenses of focal lengths $f_1$ and $f_2$ placed in contact will be: |
$\frac{(f_1+f_2)}{f_1f_2}$ $\frac{f_1f_2}{(f_1+f_2)}$ $\sqrt{f_1f_2}$ $\frac{1}{\sqrt{f_1f_2}}$ |
$\frac{(f_1+f_2)}{f_1f_2}$ |
The correct answer is Option (1) → $\frac{(f_1+f_2)}{f_1f_2}$ The power of a composite lens made of two thin lenses - $P=P_1+P_2$ $⇒P=\frac{1}{f_1}+\frac{1}{f_2}=\frac{(f_1+f_2)}{f_1f_2}$ |
