Induced EMF for a loop of variable area.
Not what you're looking for?
A circular loop of flexible iron wire has an initial circumference of 165.0 cm, but its circumference is decreasing at a constant rate of 12.0 cm/s due to a tangential pull on the wire. The loop is in a constant uniform magnetic field of magnitude 0.500 T, which is oriented perpendicular to the plane of the loop.
Find the induced EMF in the loop at the instant when 9 seconds have passed.
I thought that I could answer this like I delineate here:
1. the induced EMF = - d(phi_B)/dt (magnetic flux)
and magnetic flux = line integral of B*dA = B*A*sin(90) = B*A
If the circumference is decreasing at a rate of 12 cm/s then because C=2*pi*r
r = C/2*pi = 1.9098
so at t=9, r = 17.188
and thus:
magnetic flux = B*A = (0.500)*(pi*17.88)^2 = 1458
This is not the correct answer. What am I doing wrong?
Purchase this Solution
Solution Summary
The circumference and hence the area of a circular loop is varying. The induced EMF is calculated.
Purchase this Solution
Free BrainMass Quizzes
Intro to the Physics Waves
Some short-answer questions involving the basic vocabulary of string, sound, and water waves.
Variables in Science Experiments
How well do you understand variables? Test your knowledge of independent (manipulated), dependent (responding), and controlled variables with this 10 question quiz.
The Moon
Test your knowledge of moon phases and movement.
Basic Physics
This quiz will test your knowledge about basic Physics.
Introduction to Nanotechnology/Nanomaterials
This quiz is for any area of science. Test yourself to see what knowledge of nanotechnology you have. This content will also make you familiar with basic concepts of nanotechnology.