Answer
a) RMS voltage = $3.75V$,
Peak voltage = $5.3V$
b) Average power = $2.8125W$
Work Step by Step
a) $R=5Ohm, I_{rms}=0.75A$
Thus, RMS voltage = $R\times I_{rms}=5\times 0.75=3.75A$,
Peak voltage = $\sqrt 2 V_{rms}=\sqrt 2\times 3.75V=5.3V$.
b) Average Power = $V_{rms}\times I_{rms}=3.75\times 0.75=2.8125W$
