Question: A 12-V battery causes a current of 0.80A through a resistor.
A) What is its resistance?
B) How many joules of energy does the battery lose in a minute?
You buy a 75-W lightbulb in Europe, where electricity is delivered to homes at 240 V.
If you use the lightbulb in the United States at 120 V (assume its resistance does not change), how bright will it be relative to 75-W 120-V bulbs? [Hint: Assume roughly that brightness is proportional to power consumed.]