Question

An air bubble in a sphere having 4 cm diameter appears 1 cm from surface nearest to eye when looked along the diameter. If _am_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

Answer 1

The correct option is A

1.2 cm

v = 1 cm, R = 2 cm
By using,
$\frac{u_2}{v}-\frac{u_1}{u}=\frac{u_2-u_1}{R}$
$\frac{1}{-1}-\frac{1.5}{u}=\frac{1-1.5}{-2}$
$\Rightarrow u=-1.2cm$