Question

A light bulb uses 40.0 W of power when connected to a 110 V (DC) outlet. If the same bulb is connected to a European 220 V outlet, how much power will the bulb use?​

Answer 1

If the bulb's resistance doesn't change, the power it uses is proportional to the square of the voltage. So doubling the voltage quadruples the power.

On 220 V, the bulb uses (4 • 40w)= 160 W.

It glows very brightly.

For a very short time.

Because it also gets very hot, and burns out.

After a few seconds, it uses zero watts.