Question

A ringing alarm clock is put under a glass jar. The air is slowly removed from the space around it.
What will happen as the air is removed? (1 point)
The appearance of the clock will not change, but its sound will become fainter.
The clock will slowly become quieter and will ultimately fade from view.
The appearance of the clock and the sound of the clock will not change.
The clock will slowly become less visible, until you can only hear it.

Answer 1

"The appearance of the clock will not change, but its sound will become fainter."

Explanation: Visible light doesn't need air, so the clock still looks the same. Sound needs a medium (air) to propagate; as the air is pumped out the sound level drops and will eventually be inaudible (aside from any tiny vibration transmitted through the jar itself).