In an optical microscope, the objective lens has 0.150 cm focal length. For an object at 0.155 cm distance from the objective lens, what is the overall magnification if an eyepiece of a magnification of 8.00 is used

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.