Answer :
(a)
In order to calculate the current, we can use the formula below:
[tex]\begin{gathered} P=I\cdot V\\ \\ 18=I\cdot120\\ \\ I=\frac{18}{120}=0.15\text{ A} \end{gathered}[/tex](b)
To calculate the resistance, we can use Ohm's Law:
[tex]\begin{gathered} R=\frac{V}{I}\\ \\ R=\frac{120}{0.15}\\ \\ R=800\text{ ^^^^2126} \end{gathered}[/tex](c)
Since the power of 18 W means 18 J of energy is consumed each second, so the energy used each second is 18 J.