Question

The magnetic flux linked with a coil setisfies the relation $\varphi =4t^2+6t+9Wb$, where $t$ is the time (in $s$). The $emf$ indused in the coilat $t=2s$ is, (in V)

• A. $22$
  
• B. $18$
  
• C. $16$
  
• D. $40$
  

Answer 1

The correct option is A $22$

Given, $\varphi =4t^2+6t+9$

The induced emf , $\epsilon =\frac{d\varphi }{dt}=8t+6$

The emf for $t=2$ is $\epsilon =8\left(2\right)+6=16+6=22V$