Refractive index

The video explains the concept of refractive index, which is the ratio of the speed of light in a vacuum to its speed in a given medium. It uses the example of glass with a refractive index of 1.5, indicating that light travels 1.5 times faster in a vacuum than in glass.

What is a medium in the context of light speed?

• A vacuum where light travels fastest

• A type of glass with a refractive index

• A substance that allows light to travel through it

• A device that measures light speed

How is the speed of light in a medium defined?

• As the ratio of the speed of light in a vacuum to its speed in the medium

• As the speed of light in the medium

• As the speed of light in a vacuum

• As the speed of sound in the medium

What does a refractive index of 1.5 for glass indicate?

• Light does not travel through glass

• Light travels at the same speed in glass and in a vacuum

• Light travels 1.5 times slower in glass than in a vacuum

• Light travels 1.5 times faster in glass than in a vacuum

If the refractive index of a medium is greater than 1, what does it imply?

• Light travels faster in the medium than in a vacuum

• Light cannot travel through the medium

• Light travels slower in the medium than in a vacuum

• Light travels at the same speed in both

Which of the following is true about light speed in a vacuum compared to a medium with a refractive index?

• Light speed is faster in the medium

• Light speed is faster in a vacuum

• Light cannot travel in a vacuum

• Light speed is the same in both