“How can we calculate the efficiency of a heat engine?”
Heat Engines are one of the most widely used technologies today, being used in applications from automobiles to trains. However, our purchase of any model will be guided by the efficiency we want. So how can we measure this quantity? Well, we know that a heat engine works by taking in and putting out heat. And we also know that because of the second law of thermodynamics, some of this input heat will be converted to useful work. So what if we were to simply take the ratio of the output work and input heat (w_out/q_in) and use this as a quantifier? Well, this value is known as the Thermal Efficiency and is one of the most vital concepts of thermodynamics.