a)
We know that the power is given by:
[tex]P=VI[/tex]where V is the voltage and I is the current. In this case the voltage is 6 V and the power is 0.51 W; plugging these values and solving for the current we have that:
[tex]\begin{gathered} 0.51=6I \\ I=\frac{0.51}{6} \\ I=0.085 \end{gathered}[/tex]Therefore, the current is 0.085 A.
b)
Using Ohm's law we have that:
[tex]\begin{gathered} R=\frac{6}{0.085} \\ R=70.59 \end{gathered}[/tex]Therefore, the resistance is 70.59 Ohms