Red light wavelength 560 nm passing from air into glass

[Ry122]

Problem: red light of wavelength 560nm is passed from air into glass where its velocity is 1.96 x 10^8 m/s.
(c=3*10^8)
Find the frequency of the light in air and the wavelength of the light in glass.

Can someone please tell me what c is and what formulas i need to use.
thanks

 

[Hootenanny]

c is the symbol for the speed of light in a vacuum.

Have you met the concept of refraction?

 

[Ry122]

Is this how u could calculate the velocity?
n=vair/vglass
vglass=vair/n
(3x10^8/1.52) = 197368421.1 m/s