Question

If a current of 0.5 A flows in a 75 W light bulb when the voltage difference between the ends of the filament is 150 V, what is the resistance of the filament?

Answer 1

300 would be the best anwer.

Step-by-step explanation:

Answer 2

Power is current times voltage. Using Ohm's Law V=IR, we can express power in two additional ways:

`P=I^2R \\ P= (V^2)/(R)`
So for P=75W, we can use either of these to get R. Let's use the first one:

`75W=(0.5A)^2R \\ (75W)/(0.25A^2)=300 \Omega`