Q. A resistance of $40\ ohm$ and an inductance of $95.5\ millihenry$ are connected in series in a $50\ cycles/second$ ac circuit. The impedance of this combination is very nearly
A) 30 $ohm$
B) 40 $ohm$
C) 50 $ohm$
D) 60 $ohm$
Explanation
(c) $Z = \sqrt{R^{2} + (2\pi vL)^{2}}$
$= \sqrt{(40)^{2} + 4\pi^{2} \times (50)^{2} \times \left( 95.5 \times 10^{- 3} \right)^{2}} = 50\ ohm$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.