Question

For a heater rated 4 kW and 220 V calculate the resistance of the heater

Answer 1

220/18.18

Answer 2

I'd guess the relevant formulas are\[V=IR\]and\[P=I^2R\]
P and V are known so solve the system of I and R.

Answer 3

I think Ajay's 18.18 is a rounded-off value. It would be more exact to use \[R=V^2/P\]