Electro Magnetic Induction And Alternating Currents Question 31
Question: In a L-R circuit, the value of L is $ ( \frac{0.4}{\pi } )\ henry $ and the value of R is 30 ohm. If in the circuit, an alternating e.m.f. of 200 volt at 50 cycles per sec is connected, the impedance of the circuit and current will be [MP PET 1996; DPMT 2003]
Options:
A) $ 11.4\Omega ,17.5A $
B) $ 30.7\Omega ,6.5A $
C) $ 40.4\Omega ,5A $
D) $ 50\Omega ,4A $
Show Answer
Answer:
Correct Answer: D
Solution:
$ Z=\sqrt{R^{2}+X^{2}}=\sqrt{R^{2}+{{(2\pi fL)}^{2}}} $ =
$ \sqrt{{{(30)}^{2}}+{{( 2\pi \times 50\times \frac{0.4}{\pi } )}^{2}}}=\sqrt{900+1600}=50\Omega $
$ i=\frac{V}{Z}=\frac{200}{50}=4ampere $
