JEE Mains · Physics · STD 12 - Ray optics and optical instruments
- JEE Mains 2016
- Hard
- MCQ
A hemispherical glass body of radius \(10\, cm\) and refractive index \(1.5\) is silvered on its curved surface. A small air bubble is \(6\, cm\) below the flat surface inside it along the axis. The position of the image of the air bubble made by the mirror is seen

Pick an option to check your answer.
Answer & Solution
Correct Answer
(B) \(20\, cm\) below flat surface
Step-by-step Solution
Detailed explanation
Given, radius of herrispherical glass \(\mathrm{R}=10\, \mathrm{cm}\)
\(\therefore\) Focal length \(\mathrm{f}=\frac{10}{2}=-5 \,\mathrm{cm}\)
\(\mathrm{u}=(10-6)=-4\, \mathrm{cm}\)
By using mirror formula,
\(\frac{1}{v}+\frac{1}{u}=\frac{1}{f} \Rightarrow \frac{1}{v}+\frac{1}{-4}=\frac{1}{-5}\)
\(\Rightarrow v=20 \,\mathrm{cm}\)
Apparen the height,
\(\mathrm{h}_{\mathrm{a}}=\mathrm{h}_{\mathrm{r}} \frac{\mu_{1}}{\mu_{2}}=30 \times \frac{1}{15}=20\, \mathrm{cm}\) below flat surface.
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