Question

How much should the pressure of the gas be increased to decrease the volume by 10% at constant temperature ?

• A. 10%
• B. 9.5%
• C. 11.11%
• D. 5.11%

Answer 1

Answer: (C)

11.11%

Let, $P_1$ and $P_2$ are the initial and final pressure.
and $V_1$ and $V_2$ are the initial and final volume.
Use $P_2\times V_2$ $=$ $P_1\times V_1$
Now, $V_2$ $=$ $\frac{90V_1}{100}$
So, $P_2=\left(\frac{10}{9}\right)P_1$
Now, $P_2-P_1$ $=$ Change in pressure $=$ $\frac{P_1}{9}$
So, percentage change $=$ 11.11%