Question

an air bubble inside a rectangular glass slab ( cuboid)appear at 2 cm from one side and 3 cm from other opposite side if the refractive index of Glass is 1. 5 what is the actual width of the glass slab

Answer 1

Here
width of the slab = real depth from one face (d) + real depth from the opposite face (d')
now, we know that
refractive index = real depth / apparent depth
thus, for the one face
1.5 = d / 2cm
or
d = 3cm
and for the opposite face
1.5 = d'/3cm
or
d' = 4.5cm
so, total width of the slab will be
W = d + d' = 3cm + 4.5cm
or
W = 7.5 cm