Question

Which of the following is correct?

(a) Thermal efficiency varies directly as specific fuel consumption

(b) Thermal efficiency varies inversely as specific fuel consumption

(c) Thermal efficiency varies as root as specific fuel consumption

(d) Thermal efficiency varies as square as specific fuel consumption

Answer 1

The correct option is (b) Thermal efficiency varies inversely as specific fuel consumption

To explain: Specific fuel consumption is the ratio of fuel consumption rate to the power produced. Thermal efficiency is the ratio of the power produced to the fuel consumption rate. Hence both are inversely proportional to each other.