Electro Magnetic Induction And Alternating Currents Question 66
Question: There is a $ 5\Omega $ resistance in an ac, circuit. Inductance of 0.1H is connected with it in series. If equation of ac e.m.f. is $ 5\sin 50t $ then the phase difference between current and e.m.f. is [RPET 2003]
Options:
A) $ \frac{\pi }{2} $
B) $ \frac{\pi }{6} $
C) $ \frac{\pi }{4} $
D) 0
Show Answer
Answer:
Correct Answer: C
Solution:
$ \cos \varphi =\frac{R}{Z}=\frac{R}{\sqrt{R^{2}+{{\omega }^{2}}L^{2}}}=\frac{5}{\sqrt{25+{{(50)}^{2}}\times {{(0.1)}^{2}}}} $
$ =\frac{5}{\sqrt{25+25}}=\frac{1}{\sqrt{2}}\Rightarrow \varphi =\pi /4 $
