Electro Magnetic Induction And Alternating Currents Question 41

Question: The coefficient of induction of a choke coil is 0.1H and resistance is $ 12,\Omega $ . If it is connected to an alternating current source of frequency 60 Hz, then power factor will be [RPET 1997]

Options:

A) 0.32

B) 0.30

C) 0.28

D) 0.24

Show Answer

Answer:

Correct Answer: B

Solution:

$ \cos \varphi =\frac{R}{Z}=\frac{R}{\sqrt{R^{2}+{{\omega }^{2}}L^{2}}} $ $ =\frac{12}{\sqrt{{{(12)}^{2}}+4\times {{\pi }^{2}}\times {{(60)}^{2}}\times {{(0.1)}^{2}}}} $
$ \Rightarrow \cos \varphi =0.30 $



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