First, calculate the power used each day. Use the following formula:
[tex]P=\frac{V^2}{R}[/tex]where,
V: voltage = 240V
R: resistor = 16 Ω
Replace the previous values into the formula for P:
[tex]P=\frac{(240V)^2}{16\Omega}=3600W=3.6kW[/tex]Then, consider that the energy used in kWh, each day, is:
[tex]E=P\cdot t=3.6kW\cdot2h=7.2\text{kWh}[/tex]And in a year, the energy used is:
[tex]E^{\prime}=7.2\text{kWh}\cdot365=2628kWh[/tex]And the cost will be:
[tex]\text{cost}=(2628kWh)(\frac{21.8sen}{\text{kWh}})=57290.4sen[/tex]Hence, the cost to run the heater in one year is 57290.4sen
