An air bubble in a glass slab with refractive index 1.5 (near normal incidence) is 5 cm deep when viewed from one surface and 3 cm deep when viewed from the opposite face. The thickness (in cm) of the slab is
8
10
12
16
As we learnt in
Relation between real depth and apparent depth -
- wherein
= Refractive index of medium of incident.
= Refractive index of medium of refraction.
d = distance of object.
= apparent depth
Apparent depth=5cm from one side
Real depth=1.5x5=7.5 cm
apparent depth=3cm from other side
Real depth from other side =3x1.5cm=4.5
Thickness of slab=7.5cm+4.5cm=12cm
Option 1)
8
This option is incorrect
Option 2)
10
This option is incorrect
Option 3)
12
This option is correct
Option 4)
16
This option is incorrect