Question

In a series LCR circuit, resistance $R=10\Omega$ and the impedance $Z=10\Omega$. The phase difference between the current and the voltage is

• A. $0^{}$
• B. ${30}^{}$
• C. ${45}^{}$
• D. ${60}^{}$

Answer 1

Answer: (A)

$0^{}$

Note that the total impedance and the resistance are equal, so the capacitive and the inductive impedances cancel out. This means that the circuit is at resonance. So phase difference between current and voltage will be zero.

The phase difference can also be found from:

$\Rightarrow \varphi ={\cos }^{-1}\frac{R}{Z}={\cos }^{-1}\left(1\right)=0°$