Question

В процессе работы тепловой машины за некоторое время рабочим телом было получено от нагревателя количество теплоты 1,6 МДж, передано холодильнику 1 МДж. Определи КПД тепловой машины.

Answer 1

Ответ:

37.5%

Объяснение:

Q1=1.6 МДж     Q2=1 МДж      n=?

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n=(Q1-Q2)/Q1=(1.6-1)/1.6=0.375

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Answer 2

Calculation of Thermal Efficiency (КПД) of a Heat Engine

To determine the thermal efficiency (КПД) of a heat engine, we need to calculate the ratio of the useful work output to the heat input. In this case, we are given that the heat input to the working substance (нагреватель) is 1.6 MJ (megajoules) and the heat output to the refrigerator (холодильник) is 1 MJ.

The thermal efficiency (КПД) is defined as:

КПД = (Useful work output) / (Heat input)

Since we are not given any information about the work output, we cannot directly calculate the thermal efficiency. However, we can make some assumptions and provide a general explanation.

In a heat engine, the useful work output is obtained by converting a portion of the heat input into work. The remaining heat is rejected to the surroundings (in this case, to the refrigerator). The thermal efficiency of a heat engine is always less than 1 (or 100%) because some heat is always lost in the process.

Assuming that the heat engine operates in a reversible manner (which is an idealized scenario), we can use the first law of thermodynamics to calculate the work output. The first law of thermodynamics states that the change in internal energy of a system is equal to the heat added to the system minus the work done by the system:

ΔU = Q - W

Where: - ΔU is the change in internal energy of the system - Q is the heat added to the system - W is the work done by the system

In this case, we can assume that the change in internal energy is zero (since the system returns to its initial state). Therefore, we can rewrite the equation as:

Q = W

Substituting the given values, we have:

1.6 MJ = W

Since the work output is equal to the heat input, the thermal efficiency (КПД) can be calculated as:

КПД = (Useful work output) / (Heat input) = W / Q = 1.6 MJ / 1.6 MJ = 1

Therefore, the thermal efficiency (КПД) of the heat engine in this case is 1, or 100%. This means that all the heat input is converted into useful work output, which is an idealized scenario.

Please note that this calculation assumes idealized conditions and does not take into account any losses or inefficiencies that may occur in real-world heat engines. The actual thermal efficiency of a heat engine is typically less than 100% due to factors such as friction, heat losses, and other inefficiencies.