If a locomotive uses steam at 100°C, and dumps heat into air
at 22.0°C, what is the highest
possible efficiency it could have?

79%

Explanation:

Data obtained from the question include the following:

Input temperature = 100°C

Output temperature = 22°C

Efficiency =.?

Next, we shall convert celsius temperature to Kelvin temperature.

This is illustrated below:

T(K) = T (°C) + 273

Input temperature = 100°C

Input temperature in Kelvin = 100°C + 273 = 373K

Output temperature = 22°C

Output temperature in Kelvin = 22°C + 273 = 295K

Finally, we shall determine the efficiency of the locomotive as follow:

Efficiency = output /input x 100

Output = 295K

Input = 373K

Efficiency =?

Efficiency = output /input x 100

Efficiency = 295/373 x 100

Efficiency = 79%

Therefore, the efficiency of the locomotive is 79%.

do you have a formula possibly