This Is a Certified Answer

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
The power of an appliance is 100W means it uses 100J of energy in every second on an average when it is operated.

3 5 3

Watt is a unit for the rate of energy consumed (in the case of appliance).

If a 100-watt device is on for 10 hours, it will consume (100) X (10) = 1000 watt-hours of energy.

This is more commonly denoted as 1 kilowatt-hour (kWh). Your electric meter, like a cash register, measures the number of kilowatt-hours you consume each month. And you pay your electric supplier a rate based on $/kWh. The national average may be on the order of $0.10/kWh.

So for every 10 hours your 100-Watt appliance is running, it will cost you a whopping 10 cents.

An electrician would think more in terms of 'amps', which is a unit of current.

An appliance using 100wattts would be powered by 120 Volts; and the current draw would be 100/120, or 0.8 amps.

1 5 1
The ampere (SI unit symbol: A), often shortened to amp, is the SI unit of electric current (dimension symbol: I) and is one of the seven SI base units. It is named after André-Marie Ampère (1775–1836), French mathematician and physicist, considered the father of electrodynamics.
I hope this may be helpful.
*Ampere is equal to a flow of one coulomb per second.
**Coulomb is the practical meter-kilogram-second unit of electric charge equal to the quantity of electricity transferred by a current of one ampere in one second. It is named after French chemist Charles-Augustin de Coulomb (1736–1806). He is known for Coulomb's law.