The refractive index of glass is 1.5. The speed of light in air is 3 × 10⁸ m/s. What will be the speed of light in the glass?

3 × 10¹⁰ m/s

2 × 10⁸ m/s

3.3 × 10³ m/s

None of these

The refractive index (n) is defined as:

n = Speed of light in air / Speed of light in medium

Given:

n = 1.5

Speed of light in air = 3 × 10⁸ m/s

Rearrange the formula to solve for Speed of light in glass:

Speed of light in glass = Speed of light in air / n

= (3 × 10⁸ m/s) / 1.5

= 2 × 10⁸ m/s