Question

The magnetic flux linked with a coil varies as $\varphi =3t^2+4t+9$ . what is the magnitude of the emf at $t=2s$ ? $\varphi$ is in Wb.

Answer 1

we know,

$\frac{d\varphi }{dt}$=6t+4

at t=2seconds

$\frac{d\varphi }{dt}$=emf=16 Wb