If a 60W and a 100W bulb are in series across their normal voltage supply, which glows more?
While Rolyn’s conclusion is interesting, it is unfortunately based upon erroneous assumptions. First he (and others) assumes that the resistances of the bulbs are constant with respect to current flow. In reality, the resistance of incandescent light bulb filaments increases with temperature, and thus increase with current. Second he (and others) assumes that the brightness (luminance ) of a bulb is proportional to the current flow through it. It is actually proportional to the power, not the current. The power is calculated by multiplying the voltage drop across the bulb with the current flow through the bulb. If that isn’t complicated enough, another factor is that the brightness also depends upon the efficiency of the bulb. And my guess is that the efficiency changes depending upon the temperature of the filament. By far the easiest way of solving this problem would be by actually bulding the circuit and observing the light bulbs.
