How does the energy used by a 100 w lightbulb compare with the energy used by a 40 w lightbulb in a given amount of time? the 100 w bulb uses 2.5 times more energy. the 40 w bulb uses 2.5 times more energy. the 100 w bulb uses 60 times more energy. the 40 w bulb uses 60 times more energy.

The correct answer is
The 100 W bulb uses 2.5 times more energy

In fact, the power is the amount of energy used per unit of time. This means that the light bulb of 100 W uses 100 J in one second, and the light bulb of 40 W uses 40 J in one second, and if we compare the two numbers, we get

so, the 100 W light bulb uses 2.5 times more energy than the 40 W light bulb.