Emf induced in the windings of coil

[dmckeog]

Homework Statement

a tightly wound circular coil has 36.8 turns, each of radius .1m. the uniform magnetic field is in a direction perpendicular to the plane of the coil. the field increased linearly from 0 to .42t in a time of .251s.
what is the emf induced in the windings of the coil?

Homework Equations

emf=-N(dmagflux/dt)
dmagflux=dBA/dt
emf=-n*A*dB/dt
A=pi*r^2

The Attempt at a Solution

dB/dt is rate I determined to be .42t/.251s=1.6733tpersec

emf=-36.8*pi*.1m*.1m*1.6733t per sec=-1.934v

 

[dmckeog]

i really don't know what i have done wrong but the answer is wrong please help

 

[Redbelly98]

Your thinking and method are correct. A couple of reasons why your answer might be rejected:

• They are just looking for the magnitude of the EMF, so no "-" sign is needed
• Wrong number of significant figures in the answer.

 

[dmckeog]

thanks a lot