Question

In which way does blue light change as it travels
from diamond into crown glass?
(1) Its frequency decreases.
(2) Its frequency increases.
(3) Its speed decreases.
(4) Its speed increases.

Answer 1

Blue light changes as it travels from diamond into crown glass at its speed increases.

Answer 2

The refractive index of diamond is greater than that of crown glass.

By $n=\frac{c}v=\frac{\text{speed of light in void}}{\text{speed of light in medium}}$, we get that (4) Its speed increases.