Question

Assertion(A): Light travels faster in glass than in air.
Reason(R): Glass is denser than air.​

Answer 1

The assertion (A) is false whereas the reason (R) is correct.

Explanation:

• The glass is denser than air and the reason is correct.
• As glass is denser, hence when light passes from air to glass it will slow down.
• Light will bend towards normal when light moves from air to glass.

Answer 2

Assertion(A): Light travels faster in glass than in air.

Reason(R): Glass is denser than air.​

• The speed of light will be slower in glass and faster in air. In a scarce medium, light travels faster, while in an ostensibly thicker material, light travels slower. The optically rarer material slows down the electromagnetic wave, whereas the optically denser media accelerates it. Light is electromagnetic radiation visible to the human eye.
• The ray or wave of light bends towards the more normal at the interface when it goes from an optically cheaper to an optically deeper depth, and vice versa.
• In a vacuum with an index of refraction of 1.0, light moves at approximately 3 million km per sec, versus 200,000 kilometers per sec in glass (index of refraction 1.5).
• The refractive index is generally determined as the percentage of the light speed in air to the light speed in a vacuum.
• Because air does indeed have a refractive index of around 1.0, it is considered to be comparable to vacuum. Glass, like any other transparent solid or liquid, absorbs light more slowly. (The underlying reason for refraction is this.) In the air, light travels at a proportion of its speed in air. In a vacuum, light can just travel at the light's velocity.

Therefore, the assertion is false but the reason is true.