Factors affecting the speed of sound are :

1. temperature
2. density
3. pressure
4. only (a) and (b)

What causes sound?

There is no atmosphere on moon. Can you hear each other people on the moon’s surface?

Choose the correct word/words to complete the following sentence —

When sound travels in a medium ………. (the particles of the medium, the source, the disturbance, the medium) travels in form of a wave.