Is the brightness of a lamp dependent on the potential difference across it or the current through it?

Question

And is the brightness of a FILAMENT BULB dependent on the potential difference across it or the current through it?

Answer 1

from ohm's law, v is proportional to i and also P=vi.
the above proof shows that if one is increased the other automatically increases and is controlled by resistance factor.
so both are dependent.

Answer 2

It generally depends on both. Note that Ohm's law applies only to purely resistive elements. The bulb need not be purely resistive.

The power dissipated by the bulb is the product of the voltage and current. A lot of factors determine how much of that power is dissipated as light and how much as heat.

Even when a bulb is purely resistive, its resistance is not constant. It has a lower resistance when cold, so for a given applied voltage, the starting current is higher. As the filament temperature increases, its resistance increases and the current decreases, quickly reaching a stable equilibrium.

Answer 3

The simple answer is yes to both.

The intensity is dependant upon the power consumption. Power consumption is in watts which is volts times amps in this case; 1 volt x 1 amp = 1 watt.

This assumes the same filament bulb is exposed to the difference in voltages.

Keep in mind that the filament has a resistance. Ohm's law tells you the current is proportional to voltage with resistance being the proportionality constant or V = IR. As you increase voltage (potential) you also increase current.

Answer 4

It is dependant on both as-:
Power dissapated = Voltage x Current

Therefore increases and decreases in both affect the brightness - aswell as the resistance of the filament.