Electro Magnetic Induction And Alternating Currents Question 160
Question: A sinusoidal voltage V(t) = 100 sin (500t) is applied across a pure inductance of L=0.02H. The current through the coil is:
Options:
A) $ 10,\cos ,(500,t) $
B) $ -10,\cos ,(500,t) $
C) $ 10,\sin ,(500,t) $
D) $ -10,\sin ,(500,t) $
Show Answer
Answer:
Correct Answer: B
Solution:
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In a pure inductive circuit current always lags behind the emf by $ \frac{\pi }{2} $ .
If $ v(t)=v_{0},\sin ,\omega t $ then $ I=I_{0},\sin ,( \omega t-\frac{\pi }{2} ) $
Now, given v(t) = 100 sin (500 t) and
$ I_{0}=\frac{E_{0}}{\omega L}=\frac{100}{500\times 0.02} $
$ [\because ,L=0.02,H] $ $ I_{0}=10,\sin ,( 500t-\frac{\pi }{2} )=-10,\cos ,(500,t) $
