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An object is placed at a distance of \( 20 \mathrm{~cm} \) from the pole of a concave mirror of focal length \( 10 \)
\( \mathrm{cm} \). The distance of the image formed is
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\( \mathrm{cm} \). The distance of the image formed is
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Verified Answer
The correct answer is:
\( -20 \mathrm{~cm} \)
Using mirror formula, we have
\[
\frac{1}{f}=\frac{1}{v}+\frac{1}{u}
\]
Here, \( u=-20 \mathrm{~cm} ; f=-10 \mathrm{~cm} \).
Therefore, \( \frac{1}{-10}=\frac{1}{v}+\frac{1}{-20} \)
\[
\Rightarrow \frac{1}{v}=\frac{1}{20}-\frac{1}{10}=\frac{-1}{20}
\]
\[
\frac{1}{f}=\frac{1}{v}+\frac{1}{u}
\]
Here, \( u=-20 \mathrm{~cm} ; f=-10 \mathrm{~cm} \).
Therefore, \( \frac{1}{-10}=\frac{1}{v}+\frac{1}{-20} \)
\[
\Rightarrow \frac{1}{v}=\frac{1}{20}-\frac{1}{10}=\frac{-1}{20}
\]
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