Which of the following makes the motion of a perpetual motion machine a physical impossibility
Correct answer: B. Second law of thermodynamics
- A. First law of thermodynamics
- B. Second law of thermodynamics
- C. Third law of thermodynamics
- D. None of these
Explanation
The second law of thermodynamics states that in any energy transfer or transformation, there will always be an increase in the entropy of the universe. Perpetual motion machines violate this law because they aim to produce energy indefinitely without any input, which would decrease entropy over time, contradicting the second law.
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Alternating current varies periodically, so phase relationships become essential when current passes through a resistor, capacitor or inductor. The chapter distinguishes resistance from capacitive and inductive reactance, explains phase lead and lag, and connects changing electric and magnetic fields with the production and properties of electromagnetic waves.
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