Why did you test the resistance of the wire?
a. the current flowing through the lightbulb was too low. decreasing resistance would increase the current.
b. the current flowing through the lightbulb was too high. increasing resistance would decrease the current.
c. the current flowing through the lightbulb was too high. decreasing resistance would decrease the current.
d, the current flowing through the lightbulb was too low. increasing resistance would increase the current.

Acoal-fired plant generates 600 mw of electric power. the plant uses 4.8 x 10^6 kg of coal each day, and the heat of combustion of coal is 3.3x 10^7 j/kg. the steam that drives the turbines is at a temperature of 300° c, and the exhaust water is at 37° c. (a) what is the overall efficiency of the plant for generating electric power? (b) how much thermal energy is exhausted each day? (c) what is the change in entropy of the universe for this heat engine? (d) using the same heat reservoirs, what is the maximum possible (carnot) efficiency for a heat engine?