question_answer

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

A)  1.2 cm

B)  3.2 cm

C)  2.8 cm

D)  1.6 cm

Correct Answer: A

Solution :

 v = 1 cm, R = 2 cm By using\[\frac{{{\mu }_{2}}}{v}-\frac{{{\mu }_{1}}}{u}=\frac{{{\mu }_{2}}-{{\mu }_{1}}}{R}\] \[\frac{1}{-1}-\frac{1.5}{u}=\frac{1-1.5}{-2}\Rightarrow u=-1.2\,cm\]