Question

The refractive indices of four substance P, Q, R and S are 1.50, 1.36, 1.77 and 1.31 respectively. The speed of light is the maximum in the substance
(a) P
(b) Q
(c) R
(d) S

Answer 1

The speed of light is the maximum in the substance S, option D is correct.

Explanation:

1. Speed of light travelling in medium depend on refractive index of medium.

2. But relation between speed of light and refractive index of medium is inverse proportion.

3. Means speed of light is low in medium which refractive index is large value.

4. Speed of light is high in medium which refractive index is low value.  

5. Now form question, substance S have low refractive index. So speed of light is maximum in substance S.

Answer 2

Answer is Option (d)

Explanation:

$Refractive\ Index\ of\ y = \frac {Speed\ of\ Light\ in\ X}{Speed\ of\ light\ in\ Y}$

According to this formula,  

• The speed of light will be maximum in a substance whose refractive index is minimum.

Therefore,

• The speed of light will be maximum in the substance with less Refractive index.

The Refractive index of P = 1.50

Q = 1.36

R = 1.77  

&  

S = 1.31

S is the one with Maximum Speed of Light