How much does it cost to run a 40 watt bulb?

Answer 1

watts divided by voltage = amps

40watts divided by 230 voltage (uk) =0.17 amps

I suspect you are really asking what electricity will you have to pay for. Energy companies charge for Kilowatt hours (1 KWH = 1000 watts running for 1 hour). So a 40 W bulb running for 25 hours consumes 40 x 25 = 1000W = 1KWH. In 1 hour it consumes 40W x 1H = 40 WH = 0.04KWH

Answer 2

The first thing you have to do is find out how much you are being charged per kWh from the utility company. 40 watts is .040 kW. If the bulb was left on for an hour.040 kWh times what you are charged from the utility company and you will have your answer.

Now that you have read a simple answer, lets add reality. A 40W T-8/T-10/T-12 fluorescent bulb requires a specialized fixture for it to function. As part of that fixture a starter and ballast are included that also must be powered at nominal 80% efficiency and add cost to the user.

The next factor that must be considered has to do with environmental costs. each method of illumination does so via creation of heat. The heat must be dissipated and offset. The nominal temperature at the exciter of a 40W fluorescent tube is 110 degrees F with 70 degree F ambient environment. The nominal temperature of a fast start ballast (starter included) is 130 degrees F in the same ambient environment.

This stated, the cost to run a single 40W fluorescent tube one hour will be the sum of the 40W consumed by the bulb plus the cost to run the fixture plus the cost to offset the additional heat produced. Therefore expect to use your cost per KWh times .048 plus environmental cost.

Remember that even in incandescent lighting the environmental factors also play.

Answer 3

All household bulbs run on 120 volts.

Of course, "WATTS" is a product of the voltage and the amperage. So, while normal household current is powered by 120 volts AC, you may find that some of the off-road vehicles (with the lights mounted on the upper roll bar) may actually have lights that are rated at higher wattage than that, even though they are powered by 13.7 volts DC from the vehicle's electrical system.

The formula is W=E X I. Where "W" is the wattage, "E" is the voltage (electromotive force), and "I" is the amperage. So, using that formula, a 40 watt bulb lit by 120 volt house current would draw .333 amps, or a third of an amp.

But, a 40 watt bulb powered by a vehicle's electrical system would draw 2.919 amps.

There are also industrial application bulbs that operate on 230 volts, but with each level of voltage, the "base" is different, so that one voltage rating can not readily be inserted in another voltage application.

Answer 4

Assuming your question is implying in being on continuously then:

1 year is 31 556 926 seconds, therefore the 40W lightbulb will use 1262277040J of energy which is just below 351kwh (the standard unit of enegry used in domestic electricity suppliers).

At 24p per kwh per unit in the UK, it will come to £84.24

Answer 5

To calculate the cost of running a 40-watt bulb, you need to know the cost of electricity per kilowatt-hour in your area. For example, if the cost is $0.12 per kilowatt-hour, running a 40-watt bulb for 1 hour would cost $0.0048 ($0.12/1000 watts x 40 watts).

Answer 6

how much does it cost to have a 40W bulb on for 12 hours

Answer 7

To answer this just multiply the lamp wattage by what you are charged per kilowatt hour by your utility power company. 400 watts = .4 Kw.

Answer 8

To answer this just multiply the lamp wattage by what you are charged per kilowatt hour by your utility power company. 40 watts = .04 Kw.

Answer 9

In 25 hours a 40 W light uses 25 x 40 watt-hours, which is 1000 watt-hours, equal to 1 kWh, equal to 1 unit. So it uses 1 unit every 25 hours.