According to Ohm's law,
So the current is given as,
The power dissipated by the resistor is given as,
Hence, 3 A of current passes through the resistor and power dissipated is 36 W.
[tex]\begin{gathered} P=I^2R \\ =(3A)^2\times4\text{ }\Omega \\ =36\text{ W} \end{gathered}[/tex][tex]\begin{gathered} I=\frac{V}{R} \\ I=\frac{12\text{ V}}{4\text{ }\Omega} \\ I=3\text{ A} \end{gathered}[/tex][tex]V=IR[/tex]