Fact 1: Aprism is used for refracting light.

Fact 2: Refraction is the bending of light cause by a speed change when it passes through different media.

Given the two facts above, answer the question "What aspect of light changes when it passes from air into a prism?" with the following options: 
- power
 - seasons
 - speed
 - energy
 - a wave
 - Joules
 - heat
 - unique


 

   speed      