spherical

plane

hyperboloid

conial

2.0??10⁸ms^?1

3.0??10⁸ms^?1

2.4??10⁸ms^?1

2.8??10⁸ms^?1

violet component of white light travels slower than the red component

both red and violet travel faster at the same speed

both red and violet travel slower at the same speed

red component of white light travels slower than the violet component

620 nm

660 nm

640 nm

600 nm

k/2

k/4

k

k/8