Question

cite an experiment to show that sound needs a material medium for it's propagation

Answer 1

Answer: Activity:

Take a glass bell jar, connect it with vacuum pump and suspend an electric bell in it.

Connect electric bell with a battery.

Switch on the electric bell and hear the sound of bell.

Now remove the air completely from the bell jar using vacuum pump and observe the sound of electric bell.

It is observed that sound of electric bell does not come out after pumping out air from the bell jar.

This happens because after creating vacuum in the bell jar there were no air present through which sound wave can propagate.

This experiment shows that without medium sound cannot propagate and hence for the propagation of sound medium must be present.

Answer 2

$\huge{\boxed{\mathbb{ANSWER}}}$

WHAT IS SOUND?

• Sound is a form of energy which produces a sensation of hearing in our ears.

EXPERIMENT TO SHOW SOUND NEEDS A MEDIUM :-

• Take an electric bell and alright jar.

• Fit the bell inside the jar and attach to battery.

• With air still in jar ring the bell.

• Now take out air by vacuumization.

• Ring the bell again.

$\huge{\boxed{\sf{OBSERVATIONS\::}}}$

• Sound of bell can be heard when air is inside the jar. When air is taken out then sound cannot be heard.

$\huge{\boxed{\sf{CONCLUSION\::}}}$

• This shows that presence of medium is necessary for propagation of sound waves.