Question

explain bell jar experiment to showing sound can't travel in the vaccium with diagram

Answer 1

Take a jar fitted with a bell jar and attach a vacuum pump to it. Switch on the bell, you can hear the sound. Now switch on the vacuum pump and withdraw the air and as the air is withdrawn, the sound of the bell becomes feeble and then there is no sound. When the vacuum pump is switched off and the air is back in the jar, we can hear the sound again.
This proves that sound needs a material medium to travel i. e. sound cannot travel through vacuum