Question

Q-1) Give reason for the following ;-
In most of the cases , we cannot see the vibrations of a sound producing object with our eyes.

Q-2)When we open a gas tap for a few seconds , the sound of escaping gas is heard first but the smell of gas comes later .Why ?

Q-3) Explain why, a ringing bell suspended in a vacuum chamber cannot be heard outside .

Q-4)An electric bell is suspended by thin wires in a glass vessel and set ringing .Describe and explain what happens if the air is gradually pumped out of the glass vessel.

(*I need best answers please apas.)

Answer 1

1)yes we can't see because,it travels in wave form.
2)It is because sound travel faster than the gas.
3)because in vaccum there is not any medium present,so souns particles does not move.
4)then it will become vaccum and the sound can't be heard.
Hope this may help you.

Answer 2

HELLO THERE!!
I'm Rajdeep......

Awesome Questions!

Q1. Persistence of vision is a phenomenon due to which the image persists in our eyes even after the original image is removed. An image persists in our eyes for a period of 1/16 seconds after the original image is removed. Some objects, vibrate at such a frequency (or speed), that the image cannot persist in our eyes. Hence, we cannot see the vibration of some objects.

Q2. Smell of a gas spreads from the tap (where its concentration is high) to the other areas of the room (where its concentration is low) due to diffusion. The speed of rate of diffusion is slower than the speed of sound in air (330m/s). Hence, the sound, which reaches to our ears in the form of vibrations, reaches much faster than the smell of the gas reaches our nose by diffusion.

Q3. Sound is a form of energy which requires a material medium for its propagation (whether a solid, liquid, or gaseous medium). In vacuum, there is no particle present, hence vacuum does not form a medium. So, sound waves cannot travel in vacuum. So, when a bell rings in vacuum, the sound cannot be heard because the sound waves are not conveyed to our ears.

Q4. An electric bell is suspended by thin wires in a glass vessel and set ringing .Describe and explain what happens if the air is gradually pumped out of the glass vessel.
GOOD QUESTION, INDEED!

Note that at first, air was present in the vessel, and the air is slowly pumped out, due to which, a vacuum is created. Sound waves require a medium for their propagation and cannot propagate in vacuum. Thus, at first, we hear a loud sound of the ringing bell. When the air from the vessel is gradually pumped out, the intensity of the sound gradually decreases. Finally, when there is no air left in the jar, the sound ceases, although the bell continues ringing. This is because as the air is pumped out, vacuum is created. The medium for the propagation of the sound waves also decreases. 



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