You obtain a 100-W light bulb and a 50-W light bulb.Instead of connecting them in the normal way,you devise a circuit that places them in series across normal household voltage.If each one is an incandescent bulb of fixed resistance,which statement about these bulbs is correct?
A)Both bulbs glow with the same brightness,but less than their normal brightness.
B)Both bulbs glow with the same brightness,but more than their normal brightness.
C)The 100-W bulb glows brighter than the 50-W bulb.
D)The 50-W bulb glows more brightly than the 100-W bulb.

Question

Quizplus · Accepted Answer

When bulbs are connected in series, the bulb with the lower power rating (which corresponds to higher resistance for incandescent bulbs at a given voltage) will glow more brightly. This is because it limits the current for both bulbs, and since power dissipation (brightness) in a resistor (the bulb filament, in this case) is proportional to the square of the current times the resistance, the bulb with higher resistance (the 50-W bulb) ends up dissipating more power in this configuration.

You Obtain a 100-W Light Bulb and a 50-W Light