what happens inside the light bulb when it is off, and what happens to the electrical current in the light bulb when it is turned on?
2007-03-27 13:41:52 · 3 answers · asked by iNeedhelp 4 in Science & Mathematics ➔ Physics
When a light bulb is turned off the current stops, the filiment cools down and stops glowing.
When a light bulb is turned on there is a surge of current for a few miliseconds until the filiment starts glowing the the current goes to a steady state.
The filiment has a resistance and the current is determined by ohm's law. Voltage = current X resistance. The resistance is lower when the filiment is cold (higher current) and increases when the filiment gets hot (lower current). This is why light bulbs usually burn out just when you turn them on.
2007-03-27 13:49:41 · answer #1 · answered by John S 6 · 0⤊ 0⤋
The glowing element of a light bulb, called Tungsten filament, is bassically a coiled wire with high resistance to electric current. When the light bulb is turned on, a current passes through the tungsten filament and it becomes heated. This causes the atoms in the filament to release photons, which are particles of light. When the bulb is turned off, the electric current no longer passes through it, and the tungsten filament quickly cools off.
2007-03-27 13:57:10 · answer #2 · answered by Mirzo 1 · 0⤊ 0⤋
When it is turned on the current heats up the filament causing it to glow and gives off light. When it is turned off, nothing happens and the filament cools down.
2007-03-27 13:51:18 · answer #3 · answered by sgt 4 · 0⤊ 0⤋