| Assertion: The alternating current lags behind the e.m.f. by a phase angle of \[\frac{\pi }{2}\], when A.C. flows through an inductor. |
| Reason: The inductive reactance increases as the frequency of A.C. source decreases. |
A) If both assertion and reason are true and reason is the correct explanation of assertion.
B) If both assertion and reason are true and reason is not the correct explanation of assertion.
C) If assertion is true but reason is false.
D) If both assertion and reason are false.
E) If assertion is false but reason is true.
Correct Answer: C
Solution :
When pure inductor is connected to square of an alternating emf, then simultaneous value of alternating emf given by \[E={{E}_{0}}\,\sin \omega t\](at, and corresponding alternating Current is given by \[I={{I}_{0}}\sin \left( \omega t-\frac{\pi }{2} \right)\]. From these two equations, it follows that alternating current lags behind e.m.f. by a phase angle of \[\frac{\pi }{2}\]. The inductive reactance. \[{{X}_{L}}=\omega L=\pi .2f.L\], so when frequency increases correspondingly inductive reactance also increases.
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