The brightness of the lamp (power) depends on two factors: The voltage and the current which flow through it.
In Figure(A) as the variable reaistance increases its reaistance, the current which flow through the lamp will decrease and therefore its brightness decreases.
My question is what about the voltage across the lamp,does it decrease or increase?
In figure (B) what the factor which depend on the brightness? I read a lot of forums concerning this topic and they always state that the brightness depend on the Resistance and as the resistance increases the voltage increases
Why don't they refer the current which flow through the lamp?
(I KNOW the current is constant in series connection but the lamps are connected in parallel to the resistance so I think the current must be mentioned when we talk about brightness)