Lesson: Chapter 4 — Waves and their applications

What a wave is 4 of 4 Reset answers

Clear all your answers?

This erases every answer in this set and starts you again at question one. Your score will be gone.

Type these four numbers to confirm:

Those numbers don't match. Look at them again and type them.

Yes, clear Keep them

Question 4

Light from the sun reaches the earth even though the space between them has no air. What does this show?

A Space is full of water B Light is a sound wave C Light needs air to travel D Light is a wave that needs no material medium

The right answer is the one marked above.

Light is a wave that needs no material medium. Light travels as an electromagnetic wave, and electromagnetic waves can cross empty space.

Sound is the opposite case: it does need a medium, which is why it cannot cross empty space.

Answer the question to continue.