A question from my HW on Alternating Currents: "When a domestic electric heater is operated from a 240 V a.c. supply, an r.m.s. current of 8.0 A flows. Assuming the heater is purely resistive, calculate its resistance, mean power and maximum instantaneous power. " I don't know what is meant by "240 V a.c. supply". Is the question referring to the peak voltage or the r.m.s. voltage? Or is there another convention that is generally agreed to? This is all that is holding me back from answering the question.