In an experiment, $$200\,V\,AC$$ is applied at the ends of an $$LCR$$ circuit. The circuit consists of an inductive reactance
$$\left( {{X_L}} \right) = 50\,\Omega ,$$ capacitive reactance
$$\left( {{X_C}} \right) = 50\,\Omega $$ and ohmic resistance
$$\left( R \right) = 10\,\Omega .$$ The impedance of the circuit is
A.
$$10\,\Omega $$
B.
$$20\,\Omega $$
C.
$$30\,\Omega $$
D.
$$40\,\Omega $$
Answer :
$$10\,\Omega $$
Solution :
Total effective resistance of $$LCR$$ circuit is called impedance of the $$LCR$$ series circuit. It is represented by $$Z.$$
where $$Z = \frac{{{V_0}}}{{{i_0}}} = \sqrt {{R^2} + {{\left( {{X_L} - {X_C}} \right)}^2}} $$
Given, $${V_{AC}} = 200\,V$$
Resistance offered by inductor $${X_L} = 50\,\Omega $$
Resistance offered by capacitance $${X_C} = 50\,\Omega $$
$$\eqalign{
& R = 10\,\Omega \cr
& Z = ? \cr
& \therefore Z = \sqrt {{{\left( {10} \right)}^2} + {{\left( {50 - 50} \right)}^2}} \cr
& {\text{or}}\,\,Z = 10\,\Omega \cr} $$
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