Question

Take, bulk modulus of water $B=2100MPa$.
What increase in pressure is required to decrease the volume of $200litres$ of water by $0.004$ percent?

• A. $210kPa$
• B. $840kPa$
• C. $8400kPa$
• D. $84kPa$

Answer 1

The correct option is D $84kPa$

Given,
bulk modulus of water $\left(B\right)=2100MPa$
$=2100\times {10}^{6}Pa$
We know that,
$△P=B\left(\frac{-△V}{V}\right)$
Here, $△V=0.004$
and $V=100$
$=2100\times {10}^6\times \left(\frac{0.004}{100}\right)$
$=\frac{2100\times {10}^6\times 4}{1000\times 100}$
$=\frac{8400\times {10}^6}{{10}^5}$
$=84000Pa$
$=84kPa$.