Compare the time it takes the light to travel from your
teacher to your eye with the time
it takes sound to travel the same
distance.

Light takes less time than sound.

Explanation:

Let's say, the teacher and the student are at a distance "d" from each other.

The medium around them would be air.

And,

The speed of light in air is approx. 3× 10⁸ m/s

while, the speed of sound in air is approx. 330 m/s

We have a formula that establishes the relation between speed, distance and time.

Our hunt for time — Speed in both the scenarios is known to us whereas the distance is same.

Sound

Light

The best way of comparison is finding their ratio.

simplifying the fraction

d gets canceled and we're left with the following expression

30, being a common factor in the numerator as well as denominator, gets canceled out. and in its place remains 1/ 11

(why?

=> 30÷330 = 1÷11)

taking timeₛ to the numerator on the other side.

Therefore, we get timeₛ is approx. 10⁶ times the timeₗ.

That's a big difference, no wonder light's way much faster than sound.

As lesser the time taken to cover a distance, faster is the wave.