Question

Tie a balloon on the neck of a test tube. Keep the test tube in hot water. The balloon inflates. After some

time, keep this test tube in ice cold water. The balloon deflates. What is the reason?

eep this teat

(a) Hot air expands and rise up but cool air contracts air expe (b) Cool air expands and rise up but hot air contracts

(c) No effect of change in temperature on air

(d) None of these




please help me.... ​

Answer 1

Explanation:

Option A is the correct answer

Reason : When the boiling tube is placed in hot water, the air present in boiling tube gets heated, expands and its volume increases. The increased volume of air fills the balloon due to which the balloon gets inflated

Answer 2

Keeping the test tube in hot water the balloon inflates while keeping this test tube in ice cold water, the balloon deflates. The reason is: (a) Hot air expands and rises up but cool air contracts air expands.

When the test tube is kept in hot water

• When the test tube on which a balloon is tied on the neck is kept in hot water, then heat from hot water is transferred to the test tube.
• As a result, the air in the test tube also becomes warm.
• Now, the motion of the air molecules increases and they start to move away from each other. Thus, more volume is occupied.
• Also, the warm air starts rising up as its density decreases.
• Hence, the balloon located on the top of the test tube neck inflates when the test tube is kept in hot water.

When the test tube is kept in hot water

• On the contrary, when the same test tube is placed in ice cold water, the air molecules start getting closer and thus volume will decrease and density will increase.
• As a result, the air will come down and the balloon will deflate.