A Carnot heat engine is operating between a source at TH and a sink at TL. If it is desired to double the thermal efficiency of this engine, what should be the new source temperature? Assume the sink temperature is held constant?
1
\(\frac{{{T_L}{T_H}}}{{{T_H} - {T_L}}}\)
2
\(\frac{{T_L^2}}{{{T_H} - 2{T_L}}}\)
3
\(\frac{{T_H^2}}{{2{T_H} - {T_L}}}\)
4
\(\frac{{{T_L}{T_H}}}{{2{T_L} - {T_H}}}\)