Question

A circular coil of wire has a radius of 7 cm and contains 40 turns. A field of 0.900 T passing through the coil collapses at a uniform rate to zero in 0.200 seconds. What emf is generated in the wire?Answer choices2.77 V3.26 V4.04 V4.27 V

Answer 1

Given:

The radius of the coil, r=7 cm=0.07 cm

The number of turns, N=40

The field passing through the coil, B=0.900 T

The time interval, t=0.200 s

To find:

The induced emf.

Step-by-step explanation:

The emf induced is given by the equation,

`\begin{gathered} E=NA(B)/(t) \\ =(N\pi r^2B)/(t) \end{gathered}`

Where A is the cross-sectional area.

On substituting the known values,

`\begin{gathered} E=(40*\pi*0.07^2*0.900)/(0.2) \\ 2.77\text{ V} \end{gathered}`

Final answer:

Thus the emf generated in the wire is 2.77 V