Author Question: A light bulb, sold as long-lasting, is rated 120 W at 130 V. The increased lifetime comes from using ... (Read 86 times)

tuffie · **on:** Jul 28, 2018

A light bulb, sold as long-lasting, is rated 120 W at 130 V. The increased lifetime comes from using it at 120 V. Assuming negligible change in resistance at the different voltage, what is its power consumption at 120 V?
a. 92 W
c. 108 W
b. 102 W
d. 85 W

Question 2

A solid disk of radius R rolls down an incline in time T. The center of the disk is removed up to a radius of R/2 . The remaining portion of the disk with its center gone is again rolled down the same incline. The time it takes is:
a. T.
b. more than T.
c. less than T.
d. requires more information than given in the problem to figure out.