Question

A pair of adjacent coils has a mutual inductance of $2.5 \,H$ If the current in one coil changes from $0$ to $40 \,A$ in $0.8\, s$, then the change in flux linked with the other coil is

• A. $100\, Wb$
• B. $120\, Wb$
• C. $200\, Wb$
• D. $250\, Wb$

Answer 1

Answer: (A)

Given, $M=2.5\,H, \frac{dI}{dt}=\frac{40-0}{0.8}=50As^{-1}$
Also, $\varepsilon=M \frac{dI}{dt}=\frac{d\phi}{dt}$
or $ d\phi=MdI=2.5\left(40-0\right)$
$=100\,Wb$