Electro Magnetic Induction And Alternating Currents Question 489
Question: A varying current in a coil changes from 10A to zero in 0.5 sec. If the average e.m.f induced in the coil is 220V, the self-inductance of the coil is
Options:
A) 5 H
B) 6 H
C) 11 H
D) 12 H
Show Answer
Answer:
Correct Answer: C
Solution:
-
Initial current
$ (I_{1})=10A $ ;
Final current $ (I_{2})=0 $ ;
Time (t) = 0.5 sec and induced e.m.f. $ (\varepsilon )=220 $ V. Induced e.m.f. $ (\varepsilon ) $
$ =-L\frac{dI}{dt}=-L\frac{(I_{2}-I_{1})}{t}=-L\frac{(0-10)}{0.5}=20L $ Or,
$ L=\frac{220}{20}=11H $ [where L = Self inductance of coil]
