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 overset@A in air, has a wavelength of 4000 overset@A in glass. If the wavelength of violet light in air is 4400 overset@A , what is the wavelength in glass. (Assume R.I. for violet and red colour are same)

Light of wavelength 7200Å in air has a wavelength in glass (mu=1.5) equal to:

Light of wavelength 7200Å in air has a wavelength in glass (mu=1.5) equal to:

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 Å , then the number of waves in 1 mm length will be