Question

a fish is at a depth of 30cm below the surface of water. what will be the distance between the fish and it's image of the refractive index of water is 4/3.​

Answer 1

Answer:

7.5cm

Explanation:

We know

Refractive index=real depth/apparent depth

Hence apparent depth

=30/(4/3)=90/4=22.5 cm

Depth of image= 22.5 cm

Hence distance between fish and image=30-22.5

=7.5 cm (answer)

Answer 2

Given,

The actual depth of the fish below the surface of water = D = 30 centimeters

Refractive index of water = RI = 4/3

To find,

Distance between the fish and its image.

Solution,

We can simply solve this numerical problem by using the following process:

Let us assume that the image of the fish is at a depth of I centimeters below the surface of the water.

Mathematically, in case of refraction;

Refractive index of a medium (RI)

Refractive index of a medium (RI)= (Actual depth of the object)/(Depth of the image of the object)

Now, as per the given question;

Refractive index of water (RI)

= (Actual depth of the fish)/(Depth of the image of the fish)

=> 4/3 = 30 cm/I

=> I = 90/4 cm

Now,

The distance between the fish and its image

= (Actual depth of the fish)-(Depth of the image of the fish)

= 30 cm - 90/4 cm

= 30/4 cm = 7.5 cm

Hence, the total distance between the fish and its image is 7.5 centimeters.