Electro Magnetic Induction And Alternating Currents Question 402
Question: In a magnetic field of 0.05T, area of a coil changes from $ 101,cm^{2} $ to $ 100,cm^{2} $ without changing the resistance which is 2W. The amount of charge that flow during this period is [Orissa PMT 2005]
Options:
A) $ 2.5\times {{10}^{-6}} $ coulomb
B) $ 2\times {{10}^{-6}} $ coulomb
C) $ {{10}^{-6}} $ coulomb
D) $ 8\times {{10}^{-6}} $ coulomb
Show Answer
Answer:
Correct Answer: A
Solution:
$ \varphi =BA $
Þ change in flux $ d\varphi =B.dA $ = $ 0.05\ (101-100)\ {{10}^{-4}} $ $ ={{5.10}^{-6}} $ Wb.
Now, charge $ dQ=\frac{d\varphi }{R}=\frac{5\times {{10}^{-6}}}{2}=2.5\times {{10}^{-6}} $ C.
