If the wavelength of light is `4000 Å`, then the number of waves in `1 mm` length will be

If the wavelength of light is 4000 A, then the number of waves in 1 mm length will be ......

If the wave length of light is 2000Å , then the number of waves in I mm. length will be________.

A light wave in air enters a medium of refractive index (4)/(3) . If the wavelength of light in air is 6000Å , then the wave number of light in the medium is

A light wave in air enters a medium of refractive index (4)/(3) . If the wavelength of light in air is 6000Å , then the wave number of light in the medium is

Red light of wavelength 6400 Å in air has a wavelength of 4000 Å in glass. If the wavelength of violet light in air is 4400 Å, then the wavelength in glass is

Red light of wavelength 6400 Å in air has a wavelength of 4000 Å in glass. If the wavelength of violet light in air is 4400 Å, then the wavelength in glass is