Question

В процессе работы тепловой машины за определённое время рабочее тело получило от нагревания количество теплоты, равное 2,0 МДж, а отдало холодильнику 1,5 МДж. Вычислите КПД машины.

Answer 1

КПД= ( Q1-Q2) / Q1= (2 - 1,5) / 2= 0,5/ 2=0,25 ( 25%)

Answer 2

Calculating the Efficiency of the Heat Engine

To calculate the efficiency of the heat engine, we can use the formula for efficiency:

Efficiency (η) = (Useful energy output / Energy input) * 100%

In this case, the useful energy output is the work done by the engine, and the energy input is the heat added to the system.

Given: - Heat added to the working substance (Q1) = 2.0 MJ - Heat rejected to the refrigerator (Q2) = 1.5 MJ

We can use these values to calculate the efficiency of the heat engine.

Calculating the Efficiency

Using the formula for efficiency:

Efficiency (η) = (Useful energy output / Energy input) * 100%

The useful energy output is the work done by the engine, which can be calculated as the difference between the heat added and the heat rejected:

Useful energy output = Q1 - Q2

Substitute the given values: Useful energy output = 2.0 MJ - 1.5 MJ = 0.5 MJ

Now, we can calculate the efficiency using the formula: Efficiency (η) = (0.5 MJ / 2.0 MJ) * 100% Efficiency (η) = (0.25) * 100% Efficiency (η) = 25%

Answer

The efficiency of the heat engine is 25%.