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Question
Can you have an AC series circuit in which there is a phase difference of (a) 180° (b) 120° between the emf and the current?
Solution
Let us consider an AC series LCR circuit of angular frequency ω. The impedance of the circuit is given by,
`Z =sqrt(R^2 + (omegaL - 1/(omegaC))`
The phase difference between V and I is given by,
`tan Ø = (omegaL - 1/(omegaC))/Z`
From the above formula, we can clearly see that
`Ø ∈ = (-pi/2 , pi/2)`
So, we cannot have a phase difference of 180° or 120°.
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