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An object is placed 20cm from a concave mirror of focal length 15cm. Calculate the ...

An object is placed 20cm from a concave mirror of focal length 15cm. Calculate the linear magnification of the image formed
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  • A 0.5
  • B 1.5
  • C 2.0
  • D 3.0
Correct Answer: Option D
Explanation:
\(\frac{1}{U} + \frac{1}{V} = \frac{1}{F}\)
\(\frac{1}{V} = \frac{1}{F} - \frac{1}{U}\)
\(\frac{1}{V} = \frac{1}{15} - \frac{1}{20}\)
\(\frac{1}{V} = \frac{\text{4 - 3}}{60}\)
\(\frac{1}{V} = \frac{1}{60}\)
V = 60cm
M = \(\frac{V}{U} = \frac{60}{20}\)
M = 3.0cm

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