Answer:
the answer to that is sometimes
May be you can use the quadratic equation formular.
Power = Current *Voltage
You already have the current, but not the voltage.
But you are given resistance, and you know that
Voltage=Current*Resistance
Therefore
V=I*R=4*12=48V
So you have 48V
Now you can figure out the Power
P=I*V=4*48=192W
Therefore you have 192W.
hope this helps