Question

At $0.095/kwh, what does it cost to leave a 25 w porch light on day and night for a year?

Answer 1

Answer:

It will cost $20.81

Explanation:

Cost of Electricity

The rate of the cost of electricity is usually expressed in $/KWH because the consumption of electricity is measured in Kilowatts-hour.

If a 25W porch light is on day and night for a full year, the electricity consumption is:

25W*24 H/Day*365 Day/year* 1 year=219,000 WH

converting to KWH: 219,000 WH = 219,000 /1000 KWH = 219 KWH

The rate is $0.095/KWH, thus:

The cost of electricity is 219 KWH*$0.095/KWH= $20.81

It will cost $20.81