It can never be negative so energy is being emitted whichever way the current is moving. This is similar to friction. If I push a kg mass across the floor and back again the mass has not moved. It is exactly where it started from. But if you try it you will find that it takes you work and effort BOTH ways.
Previous question. Next question. Register Now. Remember Me. Lost Password Lost your password? Strategy The rms voltage is the amplitude of the voltage times. The impedance of the circuit involves the resistance and the reactances of the capacitor and the inductor.
The average power is calculated by Figure , or more specifically, the last part of the equation, because we have the impedance of the circuit Z , the rms voltage , and the resistance R. Significance If the resistance is much larger than the reactance of the capacitor or inductor, the average power is a dc circuit equation of where V replaces the rms voltage.
Check Your Understanding An ac voltmeter attached across the terminals of a Hz ac generator reads 7. Write an expression for the emf of the generator. Check Your Understanding Show that the rms voltages across a resistor, a capacitor, and an inductor in an ac circuit where the rms current is are given by respectively.
Determine these values for the components of the RLC circuit of Figure. For what value of the phase angle between the voltage output of an ac source and the current is the average power output of the source a maximum? The instantaneous power is the power at a given instant. The average power is the power averaged over a cycle or number of cycles. The average ac current delivered to a circuit is zero. Despite this, power is dissipated in the circuit. Can the instantaneous power output of an ac source ever be negative?
Can the average power output be negative? The power rating of a resistor used in ac circuits refers to the maximum average power dissipated in the resistor.
Problem 6. Problem 7. Problem 8. Problem 9. Problem Video Transcript scientists run, we're considering two different circuits. Numerade Educator.
Electric Charge In physics, a charge is a physical property of matter that causes it to expe…. The Electric Force The electric force is a physical force exerted by electrically charged parti…. Share Question Copy Link. Report Question Typo in question. Answer is wrong. Video playback is not visible. Audio playback is not audible. Answer is not helpful. By definition, these are. We may then write for the average power dissipated by a resistor,.
This equation further emphasizes why the rms value is chosen in discussion rather than peak values. Alternating voltages and currents are usually described in terms of their rms values.
For example, the V from a household outlet is an rms value.
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