d
(d)
$I =\frac{1}{2} \rho V A^2 \omega^2$
$\frac{I_1}{I_2} =\left(\frac{V_1}{V_2}\right) \times\left(\frac{A_1}{A_2}\right)^2 \times\left(\frac{\omega_1}{\omega_2}\right)^2$
$=\left(\frac{\frac{150}{0.5 \pi}}{\frac{00 \pi}{\pi}}\right) \times\left(\frac{5}{10}\right)^2 \times\left(\frac{150 \pi}{300 \pi}\right)^2$
$\frac{I_1}{I_2} =\frac{1}{16}$