Answer
(a) $2.704mJ$
(b) decrease
Work Step by Step
(a) We can find the required energy as follows:
$Dose \space in \space rad=\frac{dose \space in \space rem}{RBE}$
$Dose \space in \space rad=(\frac{52\times 10^{-3}}{15}\times 0.01)J/Kg$
Given that the mass of the person is $m=78Kg$
Now the energy absorbed is given as $E=(dose\space in \space rad)m$
$E=(\frac{52\times 10^{-3}rad}{15}\times 0.01J/Kg)(78Kg)$
$E=2.704mJ$
(b) We know that the energy absorbed is inversely proportional to the $RBE$ of the $\alpha$ particles, thus the energy decreases with increase in $RBE$.
