Question

Fred's lightbulb is 45% efficient, and Fran's is 75% efficient. If they both use the same amount of electric energy, which produces more light energy? ​

Answer 1

Frank's 75% efficient light bulb will shine brighter.

Step-by-step explanation:

The brightness of a bulb is gotten from the power equation;

P = I²R

The more the power rating in watts, the more the brightness.

Now, if they both use the same amount of energy but yet have different efficiency, it means we will just multiply the efficiency by the power.

Thus, 75% efficiency will yield more power than a 45% efficient one.

Therefore, Frank's light bulb will shine brighter.