How many watts of energy does it take to run a 250 watt light bulb?

Answer 1

Obviously it depends upon the technology used in the bulb, but a typical incandescent bulb is about 10% efficient in converting the electrical energy to light. So, 90% of the input power ends up as heat. Hence, a 250W incandescent bulb will produce around 225W of heat (i.e. a LOT!!!).

Answer 2

(A quick trip down memory lane to those Physics lessons!)

Power and energy are different. Energy is an amount of ability to do work / things (Joules, calories, kWh, BTU etc, VAh). You calculate the energy used by something by the power x the time it is on for (making sure you use the right units).

Power is how quickly you use or convert energy. Think big powerful sports car / lorry compared to little Smart car / bike. (Watts, Horsepower, VA). They could both use the same about of energy (ie fuel) but over the same length of time the sports car would use a lot more.

In answer to your question, 250 Watt's is the power of the lightbulb! ie how many joules of energy it uses / gives out in a second. If you meant energy, in one hour it would use 0.25 kWh (0.25 kW x 1 hour) or 900,000 Watts (250W x 60sec x 60sec).

This is a good conversion website.

http:/www.onlineconversion.com

Hope this helps,

Ollie (used to be a Physics teacher and so sort of having withdrawal symptoms)

Answer 3

A 250 watt incandescent bulb gives off over 200 watts of heat. With the exception of light that escapes out windows & open doors, all 250 watts is eventually converted to heat.

Answer 4

A 250 watt light bulb takes 250 watts of power. The energy it uses (that you pay for) is measured in watt-hours or kilowatt-hours. A 250-watt bulb running for 4 hours uses 1 kilowatt-hour.

Answer 5

At most it could use 24 h * 0.25 kW = 6 kWh (if left on all the time).

Answer 6

That depends how long you keep it turned on. 250 watts means 0.25 kilowatts - or 0.25 kWh per hour.