Question

A 100-W light bulb is plugged into a standard 120 V outlet. How much does it cost per month (31 days) to leave the light turned on?

Answer 1

4.836 dollars

Step-by-step explanation:

When the power in watts is multiplied by the amount of time the power is used we get the power in the following form.

The power in kWh is

`P=100* 31* 24* 10^(-3)\\\Rightarrow P=74.4\ kWh`

Cost of kWh = 6.5 cents (assumed)

Cost in a month is given by

`74.4* 6.5=483.6\ Cents=(483.6)/(100)=4.836\ \$`

The cost per month is 4.836 dollars per 31 days