Problem: You buy a 75-W light bulb in Europe, where electricity is delivered to homes at 240 V.
Part I: If you use the light bulb 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.
Please use great detail in explaining the solution. Thank you.