Question

A postage stamp kept below a rectangular glass slab of refractive index 1.5 when viewed from vertically above it appears to be raised by 7 .0 mm calculate the thickness of the glass slab

Answer 1

I hope this is the answer

Answer 2

Explanation:

refractive index= real depth/ apparent depth

let the distance be x

when the slab is placed in and raised by 7mm

new distance= x-7

BTP,

1.5= x/ x-7

or 1.5( x-7)= x

or 1.5 x- 10.5 = x

or 0.5 x = 10.5

or x= 10.5/5

or x= 21 mm

or x= 2.1 cm