Question

The magnetic flux $\varphi$ (in weber) linked with a coil of resistance $10\Omega$ varies with time t (in second) as $\varphi =8t^2-4t+1$. The current induced in the coil at t=0.1 sec is

• A. 10 A
• B. 0.24 A
• C. 0.12 A
• D. 4.8 A

Answer 1

The correct option is B 0.24 A

E.m.f. induced, $ϵ=\frac{-d\varphi }{dt}=\frac{-d}{dt}(8t^2-4t+1)=-\left[\right(2\times 8)t-4]=-[16t-4]$
Here, t = 0.1 s
$\therefore ϵ=-[16\times 0.1-4]=4-1.6=2.4V$
Current induced $I=\frac{ϵ}{R}=\frac{2.4}{10}=0.24A$