Question

An under water swimmer is at a depth of 12m below the surface of water. A bird is flying at a verticle height of 24m above the surface of water directly above is eyes.If n( water )=4/3 the distance below the surface of water the man appears to the bird.​

Answer 1

12th/Physics

Ray Optics

Answer :

Height of bird from surface of water = 24cm

Depth of swimmer below the surface of water = 12cm (Real depth)

Refractive index of water = 4/3

We have to find apparent depth of swimmer$.$

★ Apparent depth in a medium is the depth of an object in a denser medium as seen from the rarer medium.

• Its value is smaller than the real depth.

Apparent depth can be calculated by using this formula :

• n = RD/AD

→ n denotes refractive index of denser medium wrt rarer medium

→ RD denotes real depth

→ AD denotes apparent depth

By substituting the values, we get

➠ n = RD/AD

➠ 4/3 = 12/AD

➠ AD = 36/4

➠ AD = 9cm

∴ (A) is the correct answer!

Cheers!