What is the speed of light waves in a vacuum in units of $km/s$?

The velocity of light in a vacuum is $....$

If the absolute refractive indices of water and glass are $\frac{4}{3}$ and $\frac{3}{2}$ respectively,then what will be the ratio of the velocity of light in water to that of glass?

$A$ ray of light is incident obliquely on a glass slab. Draw a ray diagram showing the path of the light ray. Clearly,mark the angle of incidence,angle of refraction,angle of emergence,and lateral displacement of the ray. Give a formula to find the refractive index of the glass slab in terms of the angle of incidence and the angle of refraction.

What is the ratio of the velocity of light in a transparent medium with a refractive index of $1.5$ to the velocity of light in a vacuum?

What happens when a light ray incident normally on the surface of a glass slab enters from air into the glass?