Electro Magnetic Induction And Alternating Currents Question 381
Question: A magnetic field of 2 ´ 10? 2 T acts at right angles to a coil of area 100 cm2 with 50 turns. The average emf induced in the coil is 0.1 V, when it is removed from the field in time t. The value of t is [CBSE PMT 1992; CPMT 2001]
Options:
A) 0.1 sec
B) 0.01 sec
C) 1 sec
D) 20 sec
Show Answer
Answer:
Correct Answer: A
Solution:
$ e=-\frac{N(B_{2}-B_{1})A\cos \theta }{\Delta t} $
$ \Rightarrow 0.1=\frac{-50\times (0-2\times {{10}^{-2}})\times 100\times {{10}^{-4}}\times \cos 0^{o}}{t} $
$ \Rightarrow t=0.1sec $ . $ e=-\frac{N(B_{2}-B_{1})A\cos \theta }{\Delta t} $
$ \Rightarrow 0.1=\frac{-50\times (0-2\times {{10}^{-2}})\times 100\times {{10}^{-4}}\times \cos 0^{o}}{t} $
$ \Rightarrow t=0.1sec $ .
