Question

Aplastic hemisphere has a radius of curvature of 8 cm and an index of refraction of 1.6. On the axis halfway between the plane surface and the spherical one (4 cm from each) is a small object O. The distance between the two images when viewed along the axis from the two sides of the hemisphere is approximately –

• A. 1 cm
• B. 1.5 cm
• C. 3.75 cm
• D. 2.5 cm

Answer 1

Answer: (D)

2.5 cm

Answer 2

d¢ =

d¢ = $\frac { 4 } { 1.6 }$ = 2.5 cm

– = $\frac { \left( \mu _ { 2 } - \mu _ { 1 } \right) } { R }$

$\frac { 1 } { \mathrm { v } }$ – $\frac { 1.6 } { - 4 }$ = $\frac { 1 - 1.6 } { - 8 }$

v = $\frac { - 40 } { 13 }$ = – 3cm (Approx)

hence distance between images = 8 – (3 + 2.5) = 2.5 cm