Question

The flux linked with a coil any instant t is given by $\varphi =10t^2-50t+250$. instantaneous induced emF at $t=35\text{Sec}$ is

• A. $450\text{V}$
• B. $650\text{V}$
• C. $950\text{V}$
• D. $720\text{V}$

Answer 1

The correct option is B $650\text{V}$

$\varphi =10t^2-50t+250$

Instantaneous induced emF , $e=\left|\frac{d\varphi }{dt}\right|=10\left(2t\right)-50=20t-50$

$640=20t-50$

At $t=35\text{sec}$,

$e=20\left(35\right)-50=650\text{V}$