A closed loop of wire is given the shape of a circle with a radius of 0.535 m. I
ID: 1264860 • Letter: A
Question
A closed loop of wire is given the shape of a circle with a radius of 0.535 m. It lies in a plane perpendicular to a uniform magnetic field of magnitude 0.417 T, pointing out of the page.
a) If in 0.250 s the wire loop is reshaped into a square but remains in the same plane, what is the magnitude of the average induced emf in the wire during this time?
b) Which direction does the current flow?
(Maximum two tries. Note that the two tries is intentional to aid you in understanding the concepts.)
-clockwise
-counter clockwise
-no direction
Explanation / Answer
A1 = pi*r^2 = 3.14*0.535*0.535 = 0.8987465 m^2
2*pi*r = 4l
l = 2*pi*r/4 = pi*r/2 = 3.14*0.535/2 = 0.83995 m
A = l^2 = 0.83995*0.83995 = 0.352758 m^2
dA = A2 - A1 = -0.5459885
a)
induced emf = -rate of change in flux
emf = (d/dt)*B*A = B*dA/dt
emf = 0.417*0.5459885/0.25 = 0.911 V
counter clock wise
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.