Physics - Geometrical Optics Question with Solution | TestHub

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The retrace of the path after reflection from mirror rays after refraction from lens must incident towards the centre of curvature of the mirror

$$\begin{gathered} \text{Image by lense } \\ \frac{1}{\text{v}}-\frac{1}{\text{u}}=\frac{1}{\text{f}} \\ \Rightarrow \frac{1}{10+2{\text{f}}_{\text{m}}}-\frac{1}{-15}=\frac{1}{10} \end{gathered}$$

$\frac{1}{10+2{\text{f}}_{\text{m}}}=\frac{1}{10}-\frac{1}{15}\Rightarrow \frac{1}{10+2{\text{f}}_{\text{m}}}=\frac{3-2}{30}$

$10+2{\text{f}}_{\text{m}}=30\Rightarrow {\text{f}}_{\text{m}}=10\text{cm}$