Question

The refractve index if glass is 1.5. Calculate the speed if light in glass. The speed if light in air is 300 milliin m s – 1

Answer 1

Given :-

Refractive index of glass = n = 1.5

Speed of light in vaccum = c = 3 × 10^8 ms-¹

As per a relation we know that,

Refractive index = Speed of light in Vaccum/Speed of light in any medium.

Let the speed of light in medium = v

Here, the medium is glass.

n = c/v

1.5 = 3 × 10^8/v

v = 3 × 10^8/1.5

v = 2 × 10^8 ms-¹

Hence,

The speed of light in glass = v = 2 × 10^8 ms-¹.

Some facts :-

Light always travels in straight line this is because the particles of light are that much small that they don't get any disturbance but in case of Black hole. Even the particles of light bend and travels in non-uniform way.