Q. A copper bar of length L and area of cross-section A is placed in a chamber at atmospheric pressure. If the chamber is evacuated, the percentage change in its volume will be (compressibility of copper is $8 \times 10^{12}m^{2}\ N^{- 1}\ and\ 1\ atm = 10^{5}N\ m^{2})$
A) $8\ \times 10^{- 7}$
B) $8\ \times 10^{- 5}$
C) $1.25\ \times 10^{- 4}$
D) $1.25\ \times 10^{- 5}$
Explanation
(b) $\frac{1}{K} = \ \frac{\mathrm{\Delta}V/V}{\mathrm{\Delta}p}\ \ \ \ \ or\ \ \frac{\mathrm{\Delta}V}{V} = \mathrm{\Delta}p\ \left\lbrack \frac{1}{K} \right\rbrack$
Or $\frac{\mathrm{\Delta}V}{V}\ \times 100 = 10^{5} \times 8 \times 10^{- 12} \times 100 = 8 \times 10^{- 5}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.