Question

When a mark on piece of paper is focused by travelling microscope, it gives reading as 2.50 cm. Now a slab is put over it then microscope is to be moved by 2 cm. If refractive index of slab is 1.5 then thickness of slab is –

• A. 2 cm
• B. 3 cm
• C. 4 cm
• D. None of these

Answer 1

Answer: (D)

None of these

Answer 2

x = 2 cm

m = 1.5

x = t $\left( 1 - \frac { 1 } { \mu } \right)$

2 = t $\left( 1 - \frac { 1 } { 1.5 } \right)$

\ t = 6cm