Electro Magnetic Induction And Alternating Currents Question 397
Question: The magnetic flux linked with coil, in weber is given by the equation, $ \varphi =5t^{2}+3t+16 $ . The induced emf in the coil in the fourth second is [Pb. PMT 2004]
Options:
A) 10 V
B) 30 V
C) 45 V
D) 90 V
Show Answer
Answer:
Correct Answer: A
Solution:
$ |e|,=\frac{d\varphi }{dt}=\frac{d}{dt}(5t^{2}+3t+16)=(10t+3) $
when $ t=3\sec ,\ e_{3}=(10\times 3+3)=33\ V $
when $ t=4\sec ,\ e_{4}=(10\times 4+3)=43\ V $
Hence emf induced in fourth second $ =e_{4}-e_{3}=43-33=10\ V $
