Best answer: Why can a heat engine never be 100 efficient?

Why is heat engine not 100 efficient?

Why can’t we have 100 efficiency?

Explanation: No machine is free from the effects of gravity, and even with wonderful lubrication, friction always exists. The energy a machine produces is always less than the energy put into it (energy input). … That is why 100% efficiency in machines shall not be possible.

Under what conditions would a heat engine be 100% efficient?

Carnot’s interesting result implies that 100% efficiency would be possible only if Tc = 0 K—that is, only if the cold reservoir were at absolute zero, a practical and theoretical impossibility.

Why is a heat engine inefficient?

But yes, heat engines are generally quite inefficient. Ultimately, it’s because heat itself is a fairly inaccessible form of energy. Doing that removes energy from the gas so it cools and loses pressure. By repeating the compression of a hot gas and extracting energy using a piston, we can get continuous work.

Why is it that no engine can be 100% efficient What law states this?

We know from the second law of thermodynamics that a heat engine cannot be 100 percent efficient, since there must always be some heat transfer Qc to the environment. … This increases heat transfer Qc to the environment and reduces the efficiency of the engine. Obviously, then, reversible processes are superior.

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Can devices be 100% efficient?

It is not possible to have an efficiency of greater than 1 or an efficiency percentage greater than 100%. … Mechanical devices can be made more efficient through lubrication to reduce the friction between moving parts of a machine and increase the amount of useful energy transferred.

Is there any device with 100% efficiency?

Experiments demonstrate a semiconductor device that emits more power as light than it takes in electrically. Physicists have known for decades that, in principle, a semiconductor device can emit more light power than it consumes electrically.

Is Carnot engine 100 efficient?

In order to achieve 100% efficiency (η=1), Q2 must be equal to 0 which means that all the heat form the source is converted to work. The temperature of sink means a negative temperature on the absolute scale at which the temperature is greater than unity.

What is the most efficient car engine?

To date, the most thermally efficient automotive internal combustion engine belongs to Mercedes-AMG’s Formula 1 team, with an efficiency of 50 percent; AMG hopes the F1-derived engine in the Project One street-legal supercar will achieve 41-percent thermal efficiency, which would make it the most thermally efficient …