A flat coil of wire consisting of 20 turns, each with an area of 50 cm^2 is positioned so that the normal to its plane is at the angle of 30 degrees to a uniform magnetic field that increases its magnitude at a constant rate from 2.0T to 8.0T in 2.0 s.
Induced EMF(E)= -rate of change of magnetic flux/ change of time
The Attempt at a Solution
Induced EMF(E)= rate of change of magnetic flux/ change of time
or = (N)(Change of B)(A)(COS Theta)/ Change of Time
A= 50 cm^2
Change of Time= 2.0 S
COS 30 degrees= .87
Change of B= 8.0T-2.0T=6.0T
The solution as posted by the teacher was,
Induced EMF(E)= (20)(6.0T)(.005M^2)(.87)/ 2 s
= .260 V
I do not understand how 50 cm^2 becomes .005M^2
also what happened to the negative sign?