The wavelength of red helium-neon laser light in air is 632.8 nm.(a) what is its frequency? (b) what is its wavelength in glass that has an index of refractionof 1.48? (c) what is its speed in the glass?

(a)

The frequency of a wave is given by:

where

v is the wave's speed

is the wavelength

For the red laser light in this problem, we have

(speed of light)

Substituting,

(b) 427.6 nm

The wavelength of the wave in the glass is given by

where

is the original wavelength of the wave in air

n = 1.48 is the refractive index of glass

Substituting into the formula,

(c)

The speed of the wave in the glass is given by

where

is the original speed of the wave in air

n = 1.48 is the refractive index of glass

Substituting into the formula,

grav potential energy