Q. A ball falling in a lake of depth 200 m shows a decrease of 0.1% in its volume at the bottom. The bulk modulus of elasticity of the material of the ball is (Take g=$10\ ms^{- 2})$
A) $10^{9}\ Nm^{- 2}$
B) $2\ \times 10^{9}\ Nm^{- 2}$
C) $3\ \times 10^{9}\ Nm^{- 2}$
D) $4\ \times 10^{9}\ Nm^{- 2}$
Explanation
(b) $\mathrm{\Delta}p = h\rho g = 200\ \times 10^{3} \times 10{Nm}^{- 2}$
= $2\ \times 10^{6}\ Nm^{- 2}$
K = $\frac{\mathrm{\Delta}p}{\frac{\mathrm{\Delta}V}{V}} = \frac{2\ \times 10^{6}}{\frac{0.1}{100}} = \ \frac{2 \times 10^{8}}{0.1\ }\ Nm^{- 2} = 2\ \times 10^{9}\ Nm^{- 2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.