The magnetic flux linked with a coil, in webers, is given by the equation `f=3t^(2)+4t+9`. Then the magnitude of induced e.m.f. at `t=2` second will be

Options

A. `9 V`
B. `16 V`
C. `3 V`
D. `4 V`

Answer

B

Explanation

As emf, `e = (d phi)/(dt)`
`((dphi)/(dt) =` Rate oc harge of magnetic flux)
`= (d)/(dt) (3t^(2) + 4t + 9)`
`= 6t + 4+0`
So, at `t = 2s, e = 6 xx 2 + 4 = 16 V`