Question

The red light from a helium-neon laser has a wavelength of 644.6 nm in air. Find the speed, wavelength, and frequency of helium-neon laser light in air, water, and glass. (The glass has an index of refraction equal to 1.50.)speed (m/s)wavelength (nm)frequency (Hz)airwaterglass

Answer 1

air f = 4.6527 10¹⁴ Hz

water f = 3.4914 10¹⁴ Hz

glass f = 3.1027 10¹⁴ Hz

Step-by-step explanation:

The refractive index of a material is given by

n = c / v

where c is the speed of light in a vacuum c = 3 108 m / s and v is the speed of light in the material medium.

the speed of the wave is

v = λ f

we substitute

c / n = λ f

f =
`(c)/(n \ \lambda)`

The refractive indices are

air 1,00029

water 1.3330

glass 1.5

let's calculate the frequencies

vaccum

f = 3 10⁸ / 1 644.6 10⁻⁹

f = 4.6540 10¹⁴ Hz

air

f = 3 10⁸ / 1,00029 644.6 10⁻⁹

f = 4.6527 10¹⁴ Hz

Water

f = 3 10⁸ / 1.333 644.6 10⁻⁹

f = 3.4914 10¹⁴ Hz

glass

f = 3 10 ^ 8 / 1.5 644.6 10⁻⁹

f = 3.1027 10¹⁴ Hz