Q. A $20\ volts$ ac is applied to a circuit consisting of a resistance and a coil with negligible resistance. If the voltage across the resistance is $12\ V$, the voltage across the coil is
A) 16 $volts$
B) 10 $volts$
C) 8 $volts$
D) 6 $volts$
Explanation
(a) The voltage across a $L - R$ combination is given by
$V^{2} = V_{R}^{2} + V_{L}^{2}$
$V_{L} = \sqrt{V^{2} - V_{R}^{2}} = \sqrt{400 - 144} = \sqrt{256} = 16\ volt$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.