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Subject :NSO    Class : Class 7

Rihan takes an empty half litre plastic bisleri bottle. He opens the lid and fixes his mouth on the opening in such a way that there is no gap between the opening and his mouth. He observes that the bottle crushes inwards when he sucks some air out of the bottle. Which of the following statements is the reason for Rihan’s observation?

AAir pressure inside the bottle increases.
BAir pressure outside the bottle increases.
CAir pressure inside the bottle decreases.
DAir pressure outside the bottle decreases.


Ans 1:

Class : Class 7
Air pressure outside the bottle increases as while drinking the water, the air pressure inside the bottle is reduced as he drinks the water with a force acting towards his mouth. Due to this the amount of air inside reduces and there will be no force exerted on the inner walls of the bottle from the inside.

Ans 2:

Class : Class 7
Air pressure outside the bottle increases as while drinking the water, the air pressure inside the bottle is reduced as he drinks the water with a force acting towards his mouth. Due to this the amount of air inside reduces and there will be no force exerted on the inner walls of the bottle from the inside.

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