Question

You have a 20 Volt power source attached to a light bulb that you've measured has a resistance of 8 Ohms, what is the power output of this light bulb (in Watts)?

Answer 1

50 Watts

Step-by-step explanation:

For this problem, we simply apply Ohm's law:

V = IR

V / R = I

P = IV

P = ( V / R ) V

P = ( V^2 / R )

P = (20 V)^2 / 8 Ω

P = 400 V^2 / 8 Ω

P = 50 Watts

Hence, the power consumed by the lightbulb is 50 Watts.

Cheers.