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Two thin lenses have a combined power of +9D. When they are separated by a distance of $20 \mathrm{~cm}$, their equivalent power becomes $+\frac{27}{5}$ D. Their individual powers (in dioptre) are
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Verified Answer
The correct answer is:
3,6
Given,
$$
\begin{gathered}
P_{1}+P_{2}=9 \\
P=P_{1}+P_{2}-d P_{1} P_{2} \\
\frac{27}{5}=9-\frac{20}{100} \times P_{1} P_{2}
\end{gathered}
$$
Hence, the above equation is correct for
$$
P_{1}=3 \text { and } P_{2}=6 \text {. }
$$
$$
\begin{gathered}
P_{1}+P_{2}=9 \\
P=P_{1}+P_{2}-d P_{1} P_{2} \\
\frac{27}{5}=9-\frac{20}{100} \times P_{1} P_{2}
\end{gathered}
$$
Hence, the above equation is correct for
$$
P_{1}=3 \text { and } P_{2}=6 \text {. }
$$
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