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To calculate watts you need two of the three: Voltage (V), Current (A) and Resistance (ohm).

Power (Watts) = (V^2) / R = (I^2)R = VI

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Convert 7.8 watts into lumens?

You cant convert directly between Watts and Lumens. They are measuring completely different things.Lumens measure the flux of a light being produced by a light source or received by a surface, while Watts measure the amount of power used.You could have a higher power device, but with less light then a low power one. It just depends on the light.Unless the flashlight manufacturer already has the Lumens and Watts listed, you won't be able to find out.AnswerThe watt is the radiometric unit for power, whereas the lumen is the photometric unit for power. In the case of a lamp, the watt is the product of the supply voltage and load current drawn by the lamp and describes the power input to the lamp. The lamp's power output is termed 'luminous flux' and the amount of luminous flux produced by a lamp depends upon it efficacy (NOT 'efficiency'), which is the ratio of input power expressed in watts to the luminous flux (i.e. output power) expressed in lumens -i.e. watts per lumen.The efficacy of a lamp depends upon the type of lamp -i.e. its principle of operation. Generally, incandescent lamps have relatively low values of efficacy, whereas fluorescent or other 'energy efficient' (e.g. LED) lamps have relatively high values of efficacy.To answer your question, it is necessary to know the typeof lamp to which you refer. In the absence of that information, I suggest that you search for 'efficacy of lamps' on the internet, in order to determine the efficacy of your particular lamp. Once you know that, you simply then multiply that efficacy by the number of watts (7.8) in order to determine the number of corresponding lumens.


When you turn on a lamp and the light bulb becomes warm which energy conversion causes this heating of the light bulb?

Electrical energy absorbed by the lamp's filament produces thermal energy as well as light.


How many kilowatt do 100 watt bulbs use?

That depends both on the light bulb's power rating, and how long you want to light it! Use the formula: energy = power x time If the power is in watts and the time in seconds, then the energy will be in joules (= watt-seconds). Alternately, if the power is given in watts, you can divide by 1000 to convert to kilowatts. Then, if you multiply by hours, you get kilowatt-hours. Note that the unit used by utility companies tp charge you is kilowatt-hours.


Voltage of 12 volt source. Each lamp is rated at 6 watts at 12 volts. The lights are connected with a cable of two wires each 0.03 ohms and with length of 10 m. calculate voltage drop on each lamp.?

The question is defective. It talks about plural 'lights', but it doesn't tell how many there are, or in what configuration they're connected to the 12-volt power supply. All of that stuff has a substantial effect on the correct answer. (But I don't think the 10m length of the cable has any at all.)


How do you calculate the energy dissipation by bulbs of different power rates connected in series and in parallel?

For lamps in parallel, it's straightforward, as you only need to add the individual power ratings to find the total power rating and multiply this value for the time over which they operate, to determine the energy dissipation.For lamps in parallel, it's far more complicated. Lamps in parallel are not subject to their rated voltages and, so, cannot operate at their rated powers. In fact, the lamp with the lowest power rating will actually burn the brightest! Trying to calculate what is going on is further complicated by the fact that there is significant difference in the resistance of a lamp when it is operating at its operating temperature and when it is cold, and you cannot determine these resistances theoretically. So, while you can determine the answer to your question experimentally -by measuring the current and voltage- it is not practical to calculate the answer you are looking for.

Related Questions

What is the difference between LED and Energy Saver Lamps?

I am not sure. But what I know is that LED or LED lampen is an example of an energy saver lamp.


Why does energy saver give more light than electric bulb of same volt?

First of all, it is not volts that counts, but watts. Watts indicate how much you will pay for your electricity bill. (watts, multiplied by the time you have it on, actually - watts is a unit of power.) Of course, you can't create energy from nothing. What really happens here is that the traditional incandescent light-bulb is extremely wasteful - 90% or 95% of the energy gets converted to heat. The fluorescent light wastes less, but there is still room for improvement.


Calculate the current taken by a 100 watts lamp having a working resistance of 200?

0.02 amperes


How many watts does a lamp use when it is turned on?

The number of watts a lamp uses when turned on depends on the type and wattage of the bulb. Common incandescent bulbs typically range from 40 to 100 watts, while LED bulbs are more energy-efficient and can range from 4 to 20 watts.


How bright is 950 lumens?

220 lumens is equal to a tungsten incandescent light bulb of 15 watts. Halogen lamp 20 watts. Fluorescent lamp 60 watts. LED lamp 60 watts. high pressure sodium vapour lamp 117 watts. Mercury vapour lamp 50 watts or 17.32 candle power


How much power does a bulb use?

Bulbs for domestic use are available between 3 watts and 100 watts. Bulbs used in large areas such as theatres and street lighting can be up to 2 kilowatts.AnswerA lamp doesn't 'use' power, it uses energy. Power simply tells you the rate at which it consumes energy. So, you can ask how powerful a lamp is, but you can't ask how much power it uses!


How many volts it takes to cause a current of 1.95 amps to exist in a 200 watt lamp?

The formula to calculate the relationship between amps, volts and watts is Volts X Amps = Watts or Volts = Watts / Amps or Amps = Watts / Volts therefore; 200 Watts divided by 1.95 Amps is 102.5641 Volts.


How much energy is produced by a lamp?

A lamp doesn't really produce energy; it converts it. It even wastes some energy - with some lamps, a large percentage of energy is wasted (converted to heat).The amount of energy used by a lamp depends on its wattage (which you can usually read directly from the light bulb), and how long you have it turned on. Watts is a unit of power; meaning, energy converted per unit time. You can read the amount of watts from the light bulb (and from many other electrical equipments - if watts is not indicated, you may be able to find amperes and volts - multiply both to get watts). Typical power consumption for modern (fluorescent) light bulbs is 15-40 watts; older (incandescent) light bulbs are more wasteful, using 60, 100, or even more watts - but wasting much of that power, since a large percentage of this power is converted to heat, instead of light.


How do you figure out how many watts a lamp post produces?

A lamp post produces exactly zero watts, just like my computer produces zero watts. It is a user of electricity, not a producer. The amount of electricity used will depend on the bulb that is used in the lamp post.


How many joules of electrical energy is transferred per second by 6V 0.5 A lamp?

Power = V x A = 6 x 0.5 = 3 watts = 3 joules per seconddissipated by the lamp into the surrounding environmentin the form of heat and light.


How many watts does a mini lamp use?

6 watt bulb for mini lamp


What is better using a 50 watt 240VAC lamp or a 60 watt 230VAC lamp from energy delivering and power saving point of view?

Since the utility company bills you on watts used per hour, the lower the amounts of watts you use the more money yo will save.