\(B = V \frac{dP}{dV}\)
Finding the magnitude of the change in the volume:-
70 x 109 =\(V \frac{dV}{dx} \times 10^3 \times 10 \times 5 \times 10^3\)
7 x 109 = V/dV x 106 x 5
\(7000 = \frac{V}{dV} \times 5\)
\(\frac{dV}{V} = \frac{5}{7000}\)
V = l3
\(\frac{dV}{V} = 3 \frac{dI}{I}\)
\(dI = \frac{5}{21000}\)
dl = 0.238 mm = 0.24mm