# User Forum

Subject :NSO    Class : Class 7

In the figure, bottle is filled with lukewarm water and then emptied and cap was put tightly. Then cold water was poured on it. The shape of the bottle gets distorted.

Statement 1: Atmospheric pressure is more than air pressure inside the bottle as the air was driven out.
Statement 2: Air exerts pressure on surfaces with which it comes in contact.

A Statement 1 is the conclusion of statement 2.
B Statement 2 is the conclusion of statement 1.
C Only statement 1 is correct.
D Only statement 2 is correct.

## Ans 1:

Class : Class 9
reason :the initial air was driven out of the bottle as the steam occupied the space inside. When it was emptied and capped tightly , some steam still remained inside the bottle. when cold water was poured over it , the steam condensed and turned into water droplets , which cause the reduction in air pressure inside the bottle. That is why , as the air pressure inside was lesser than the outside one , the bottle got crumpled (shrinked) to compensate the lose of air pressure. That is why both the options are correct.

## Ans 2:

Class : Class 8
yes D is the correct answer

Class : Class 10

## Ans 4:

Class : Class 9
But I thought that it was hot steam, so high temperature means low pressure and when it comes in contact with cold water(high pressure), it sinks. I didn't think about steam getting condensed and causing reduction in pressure. Well, we should check both the points. Anyways, according to me, both conclusions are correct. That is hot and cold (difference in pressure by temp) and reduction of air pressure, both are correct. So it can be either option A or D

## Ans 5:

Class : Class 10
A IS CORRECT ANSWER

## Ans 6:

Class : Class 6
no air could come out of the bottle, so D is the correct answer.

Class : Class 10