All of the electrical power is dissipated as internal energy.Power is how much energy is dissipated per second. So first we needto find the Power which is equal to \(\displaystyle{I}\cdot{V}\).

To find the energy dissipated you multiply power by the amountof time the appliance is operated. The time must be inseconds.

To find the cost of using the iron for 20 min you need the power in the first part and convert it to kW by dividing by1000 and multiply by the number of hours it is in use which is.3333 and finally multiply by the cost per kWh.

To find the energy dissipated you multiply power by the amountof time the appliance is operated. The time must be inseconds.

To find the cost of using the iron for 20 min you need the power in the first part and convert it to kW by dividing by1000 and multiply by the number of hours it is in use which is.3333 and finally multiply by the cost per kWh.