[tex]\displaystyle I = \dfrac{u}{R} \Rightarrow R = \dfrac{u}{I} = \dfrac{9 \ V}{0.45 \ A} = 20 \ \Omega. \newline
P = \dfrac{\Delta uq}{\Delta t} = Iu = 0.45 \ A \cdot 9 \ V = 4.05 \ \dfrac{J}{s} = 14580 \ \dfrac{J}{h} = 14.58 \ \dfrac{kJ}{h}.[/tex]
