A pet gecko perched on top of a branch in a tank has 1.5 J of potential energy with respect to the bottom of the tank. If the gecko has a mass is 0.2 , how high above the bottom of the tank is the gecko?

Answer (d) the universe had cooled enough for atoms to combine, protons and neutrons were too far apart to form nuclei;

If the heat engine is a perfect carnot cycle engine, thenefficiency = (t2-t1)/t2   where t1=temperature of cold reservoir ( ° k) = 135            t2=temperature of hot reservoir ( ° k)   = 325thereforeefficiency = (t2-t1)/t2 = (325-135)/325 = 0.5846 = 58%  note: this is the theoretical maximum efficiency of a perfect heat engine.   real-life engines do not achieve this value.