Question

An object is placed 5 cm from an convex air-glass interface of radius of curvature 10 cm as shown. If the refractive index of glass is 1.5, determine the location of image from the interface.

• A. 10 cm, left
• B. 5 cm, right
• C. 5 cm, left
• D. 10 cm, right

Answer 1

The correct option is A 10 cm, left

Given:
$u=-5cm$
$R=10cm$
${\mu }_1=1$
${\mu }_2=1.5$

Using refraction formula at spherical surface,
$\frac{{\mu }_2}{v}-\frac{{\mu }_1}{u}=\frac{{\mu }_2-{\mu }_1}{R}$
$\frac{1.5}{v}-\frac{1.0}{-5}=\frac{1.5-1}{10}$
$\frac{1.5}{v}=\frac{0.5}{10}-\frac{1}{5}$
$v=-10cm$

The image is formed 10 cm left to the spherical surface.