Question

Flux $\phi$ (in water) in a closed circuit of resistance 10 $\Omega$ varies with time t (in sec) according to the equation $\phi =6t^2-5t+1$. What is the magnitude of the induced current at $t=0.25$s?

• A. 1.2 A
• B. 0.8 A
• C. 0.6 A
• D. 0.2 A

Answer 1

The correct option is D 0.2 A

$emf=-\frac{d\varphi }{dt}=-12t+5$

current = $-\frac{emf}{10}=-1.2t+0.5$

current at $t=0.25s$,

$=-1.2\times 0.25+0.5=0.2A$