Question

The flux linked with a coil at any instant $t$ is given by, $\varphi =10t^2-50t+250$. The induced emf at $t=3$ sec is :

• A. $-190V$
• B. $-10V$
• C. $10V$
• D. $190V$

Answer 1

Answer: (B)

$-10V$

It is given $\varphi =10t^2-50t+250$
Induced emf $\left(e\right)=-\frac{d\varphi }{dt}=-(20t-50)$
$t=3sec$
$e=\frac{-d\varphi }{dt}=-10V$