Question

A 60w bulb has a higher resistance than a 100w bulb, since the power rating is given assuming that the bulb is connected to a 120v source by itself. If you connect a 60w bulb and a 100w bulb in series to an outlet, which will shine brighter?.

Answer 1

Voltage drop across any components in series is proportional to its resistance. 60W bulb has higher resistance than 100W bulb if both the bulbs were rated for same voltage. So higher voltage drop will be across a 60W bulb.

In parallel voltage drops will be same across both the bulbs but current through it will be inversely proportional to the resistance. So 100W bulb draws more current than 60W bulbs.

60W dissipates more energy than 100W bulbs when in series and 100W bulbs dissipates more energy when in parallel.