How is energy transferred from a battery to a torch bulb?

With copper wire.

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Improved Answer By: AP_MET

The voltage x amps current of the battery discharges electrical wattage power in the form of electons passing through a tungsten filament.

This tungsten filament is built within a glass bulb which has had all air (78% nitrogen & 21 % oxygen) evacuated from it and filled with an inert nobel gas.

The tungsten filament will become extremely hot as electrical wattage passes through it and will glow nearly white-hot within the non-air gas inside of the glass bulb.

The energy transfer from the battery to the light bulb's filament is as follows:

Chemical energy from the battery converted into electrical energy passed through the tungsten filament converted into heat energy then into light energy.

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