Assertion (A): An empty test tube placed in water in a beaker with its mouth outside the water surface appears silvery when viewed from a suitable direction.

Reason (R): The substance in water appears silvery due to refraction of light.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true and R is not the correct explanation of A.
3. assertion is false but reason is true.
4. assertion is true but reason is false.

Assertion (A): A ray of light travelling from a rarer medium to a denser medium, slows down and bends away from the normal.

Reason (R): The speed of light is higher in a rarer medium than in a denser medium.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true and R is not the correct explanation of A.
3. assertion is false but reason is true.
4. assertion is true but reason is false.

An object placed in one medium when seen from the other medium, appears to be vertically shifted. Name two factors on which the magnitude of the shift depends and state how does it depend on them.

Prove that,

$\text {Refractive index} = \dfrac {\text {Real depth}}{\text {Apparent depth}}$