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IGCSE PHYSICS DOUBTS HERE !!!!

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Kabab:
A simple Question:
Increasing voltage or increasing current changes the brightness of a lamp?
Like a 230W lamp is used so
A current supply of 5A and 46V will be brighter or supply of 2A and 115V

:D
Thanks

NotAbod:
both current and voltage contributes to the brightness of the lamp.
Brightness is affected by power.
power = Voltage x current
the bulb needs 230W to work at full energy.
5x46 = 230W
2x115= 230W
in both cases, the power supplied is 230
so the brightness will be the same for both
:)
Transistor in few mins ;)

Kabab:

--- Quote from: AboD on April 19, 2011, 04:44:11 pm ---both current and voltage contributes to the brightness of the lamp.
Brightness is affected by power.
power = Voltage x current
the bulb needs 230W to work at full energy.
5x46 = 230W
2x115= 230W
in both cases, the power supplied is 230
so the brightness will be the same for both
:)
Transistor in few mins ;)

--- End quote ---
what if 2 lamps are place in parallel to each other and battery as well. SO will the lamp glow at full brightness or half brightness.

NotAbod:

--- Quote from: DeMoNiC on April 19, 2011, 04:54:20 pm ---what if 2 lamps are place in parallel to each other and battery as well. SO will the lamp glow at full brightness or half brightness.

--- End quote ---
well, full brightness, both of them
in parallel circuits, they will all get the same voltage, so if the battery is labelled 3V, and the lamp need 3V to work, then both will work at full brightness, because they are getting the same voltage (3V) , whereas if u connect the samp circuit in series, each lamp woud get 1,5V (if they are similar) and they both would glow at half brightness.  ;D

Kabab:

--- Quote from: AboD on April 19, 2011, 05:07:17 pm ---well, full brightness, both of them
in parallel circuits, they will all get the same voltage, so if the battery is labelled 3V, and the lamp need 3V to work, then both will work at full brightness, because they are getting the same voltage (3V) , whereas if u connect the samp circuit in series, each lamp woud get 1,5V (if they are similar) and they both would glow at half brightness.  ;D

--- End quote ---
Doesn't this prove that voltage changes the brightness of lamp ::)

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