Question

The magnetic flux linked with a coil satisfies the relation $\varphi =4t^2+6t+9$ Wb, where t is the time in second. The emf induced in the coil at $t=2s$ is

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

Answer 1

Answer: (A)

$22V$

It is given that: $\varphi =4t^2+6t+9Wb$

Emf induced in the coil is equal to the rate of change of flux through it.

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

Thus, emf induced at $(t=2s)=8\left(2\right)+6=22V$