Question

Statement I: Velocity of light is constant in all media.
Statement II: Light is an electromagnetic wave which has constant velocity in all media.

• A. If both statements are true and statement II is the correct explanation of statement I.
• B. If both statements are true but statement II is not the correct explanation of statement I.
• C. If statement I is true but statement II is false.
• D. If both statements are false.

Answer 1

Answer: (D)

In vacuum, velocity of all the components of light is same which is $c$.
Now, in medium, velocity of light is given as
$v=c /\left(\varepsilon_{ r } \mu_{ r }\right)^{1 / 2}$
So, as the medium changes (or medium's permeability and permittivity changes), the velocity changes.