Question

Which example best demonstrates Charles’s law?

Answer 1

Answer:

A

Explanation:

The Charles law states that the volume of an ideal gas increases when temperature is increased under constant pressure. The pressure inside the balloon is always equal to the atmospheric pressure. Therefore answer A demonstrate the Charles law.

Answer 2

Answer:

D.  A syringe pulls in air as the plunger is pulled back.

Explanation:

As per Charles’s law  

At constant pressure for a given amount of a gas,

Volume is directly proportional to its temperature.

Directly proportional means when one increases the other one too will increase. That is when volume increases temperature too will increase. When volume decreases, temperature too will show a decrease.

Option A tells us that the volume of the hot air balloon increase due to the rise(increase) in temperature as the balloon is heated

Thus the expression is $V \propto T$

$\frac {V}{T} = k$ where k is a constant  

When there is a change in the volume and temperature the expression will be

$\frac {V_1}{T_1} = \frac {V_2}{T_2}$

where $V_1$ and $T_1$ are the initial volume and initial temperature and $V_2$ and $T_2$ are the final volume and temperature.