Question

An air bubble in sphere having $4cm$ diameter appears $1cm$ from surface nearest to eye when looked along diameter. If ${}^a{\mu }_g=1.5$ the distance of bubble from refracting surface is

• A. $1.2cm$
• B. $3.2cm$
• C. $2.8cm$
• D. $1.6cm$

Answer 1

The correct option is A $1.2cm$

Given,

$V=1$ cm

$R=2$ cm

By using,

$\begin{array}{c}\frac{{\mu }_2}{v}-\frac{{\mu }_1}{u}=\frac{{\mu }_2-{\mu }_1}{R}\\ \frac{1}{-1}-\frac{1.5}{u}=\frac{1-1.5}{-2}\\ \Rightarrow u=-1.2cm\end{array}$

Option $A$ is correct.