Why I*ε Cannot be Used to Calculate Power

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SUMMARY

The discussion clarifies that the formula I*ε cannot be used to calculate power in pure LC circuits, where resistance (R) equals zero. In such circuits, neither inductors nor capacitors absorb energy, as they only store it. Power generation is solely associated with resistive components, which dissipate energy. Therefore, in the absence of resistance, no power is generated in pure LC circuits.

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Homework Statement
In a series RLC circuit the rms value of the generator emf is ε and the rms value of the current is i. The current lags the emf by Φ, The average power suppplied by the generator is given by:

A. (iε/2) cos Φ
B. iε
C. i^2/Z
D.( i^2)Z
E. (i^2)R

ans: E
Relevant Equations
P = IV = I^2R = V^2/R
Why can't we calculate use I*ε to obtain the power?
 
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If it is a pure LC circuit (R=0) (or pure L or pure C) there will be no energy/power absorbed.
 
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Keith_McClary said:
If it is a pure LC circuit (R=0) (or pure L or pure C) there will be no energy/power absorbed.
I think I got what you mean, but I would like to double check.
Is it because inductor and capacitor both can store energy while resistance only dissipates energy, and thus resistance is the only electric accessory that can generate power?
 
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Keith_McClary said:
@hidemi Right.
Thank you for confirming!
 

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