Question

Calculate the speed at which red light travels through acrylic Calculate the speed at which blue light travels through acrylic.

Answer 1

Acrylic has a refractive index of 1.49.

If 'c' is the velocity of light in vaccum, then velocity of light through a medium of refractive index 'k' is given by -

c' = c / k

so, speed of red light through acylic = c / 1.49 = (3 x 10^8) / 1.49 = 2.013 x 10^8 m/s

Speed of blue light through acrylic will also be the same as the red light because both the colour have the same velocity through vaccum.

Only refractive index of a medium affects the velocity of light.