An alarm bell is kept inside a vessel as shown in Fig. 13.1. A person standing close to it can distinctly hear the sound of alarm. Now if the air inside the vessel is removed completely how will the loudness of alarm get affected for the same person?

Question

An alarm bell is kept inside a vessel as shown in Fig. 13.1. A person standing close to it can distinctly hear the sound of alarm. Now if the air inside the vessel is removed completely how will the loudness of alarm get affected for the same person?

Philoid · Accepted Answer

First when the alarm bell is kept inside a vessel, the person standing near it can hear the sound coming from air and water separately.

But when the air is removed from the bottle, this means there is vacuum in the bottle. As we know that sound cannot travel through vacuum and as a result, the person cannot hear the sound of alarm.