A Carnot engine has an efficiency of 35.2% when the hot reservoir temperature is 767°C.
If we want to improve the efficiency to
30.1%, what should be the temperature of
the hot reservoir, assuming everything else
remains unchanged?
Answer in units of °C.

Which device uses ac current to operate?

Why is alternating current more effective at long–distance travel than direct current? a. the power lines are made out of conductors. b. transformers increase or decrease voltage as needed. c. the ac generator is more efficient. d. ac has lower voltage than dc.

The discovery that the universe appears to be expanding led to a widely accepted theory called a.) the big bang theory b.) the doppler effect c.) hubble’s law d.) solar nebular theory e.) the seyfert theory