Final answer:
The speed of light in air is approximately 3.00 × 10^8 m/s and in crown glass it is approximately 2.00 × 10^8 m/s. The speed of light in a medium depends on the refractive index of the material.
Step-by-step explanation:
The speed of light in air is approximately 3.00 × 108 m/s and the speed of light in crown glass is approximately 2.00 × 108 m/s. The speed of light in a medium depends on the refractive index of the material. When light travels from one medium to another, it changes speed and direction due to refraction.