The flux associated with coil changes from 1.35 Wb to 0.79 Wb within `(1)/(10)`s. then, the charge produced by the earth coil, if resistance of coil is `7Omega` is

Options

A. 0.08 C
B. 0.8 C
C. 0.008 C
D. 8 C

Answer

A

Explanation

As `I=(e)/(R)=(dphi)/(Rdt)`
or `Idt=(dphi)/(R)`
Integrating the above equation, we get
`intIdt=int(dphi)/(R)` or `q=(phi)/(R)`
If coil contains N turns, then `q=(Nphi)/(R)`
If there is flux change `Deltaphi`, then
`q=(NDeltaphi)/(R)=(1)/(7)xx(1.35-0.79)=0.08V`