Answer
Thermal energy is produced in the block at a rate of $~~240~W$
Work Step by Step
A deuteron is a particle consisting of a proton and a neutron. Thus it has a charge of $e$
We can find the rate at which the deuterons strike the block:
$\frac{15\times 10^{-6}~A}{1.6\times 10^{-19}~C/deuteron} = 9.375\times 10^{13}~deuterons/s$
The deuterons strike the block at a rate of $~~9.375\times 10^{13}~deuterons/s$
We can find the rate at which thermal energy is produced in the block:
$P = (9.375\times 10^{13}~deuterons/s)(16\times 10^6~eV/deuteron)(1.6\times 10^{-19}~J/eV)$
$P = 240~W$
Thermal energy is produced in the block at a rate of $~~240~W$
