question_answer

In an LCR series circuit, the voltage across each of the components. L, C. and R is 50 V. The voltage across the LC combination will be:

A) 50 V                                      

B) 0 V

C) 50\[\sqrt{2}\] V               

D) 100 V

Correct Answer: B

Solution :

Key Idea : Voltage across inductance leads current by \[{{90}^{o}},\] while across capacitor lags behind current by \[{{90}^{o}}.\] Let an alternating emf \[E={{E}_{0}}t\sin \omega \]ot be applied to a circuit containing inductance (L), a capacitance (C) and a resistance R all joined in series. The same current will flow How in all the three and the vector sum of the potential differences across them will be equal to the applied emf. \[{{V}_{R}}\]is in phase with I but \[{{V}_{L}}\]leads i by\[{{90}^{o}}\] while \[{{V}_{C}}\]lags behind i by \[{{90}^{o}}\]Hence, voltage across the LC combination  will be OV.