Question

A fish seems to be at a depth of 75cm from the surface. What is the actual distance from the
20
surface? (Refractive index of water is 1.33).
(Ans - 100 cm)
​

Answer 1

$\LARGE{ \underline{\underline{ \sf{Required \: answer:}}}}$

GiveN:

• A fish is seems to be a depth of 75 cm.
• Refractive index of water = 4/3 or 1.33

To FinD:

• The actual depth of the fish?

Step-by-Step Explanation:

Refractive index in terms of Real and apparent depth can be defined as:

$\boxed{ \rm{ \mu = \frac{real \: depth}{apparent \: depth} }}$

We have the value of refractive index and apparent depth. So, let's find the real/actual depth of the fish.

⇒ μ = Real depth / Apparent depth

⇒ 4/3 = Real depth/75 cm

⇒ Real depth = 75 cm × 4/3

⇒ Real depth = 100 cm

Hence,

• The actual depth of the fish or the actual distance from the surface of water is 100 cm.

Answer 2

Answer:

$\huge \sf \: given$

• Depth of fish from the surface = 75 cm
• Refractive index of water = 4/3

$\huge \sf \: to \: find$

actual distance from the 20 surface

$\huge \sf \: answer$

$μ = \dfrac{real \: depth}{apparent \:depth }$

$\dfrac{4}{3} = \dfrac{real \: depth}{75}$

$real \: depth \: = 75 \times \dfrac{4}{3}$

$\huge {\fbox {\blue {100 \: cm}}}$

The actual depth of the actual distance from the surface of water is 100 cm.