A metal ring with resistance of .24 ohms and diameter 18cm is rotating at a cons
ID: 1466425 • Letter: A
Question
A metal ring with resistance of .24 ohms and diameter 18cm is rotating at a constant rate of 12 Hz in a uniform magnetic field with constant magnitude 1.2mT. The ring rotates counter clock wise. The area vector of the ring initially points out of the page, in the same direction of the magnetic field but changes as the ring rotates.At this moment what is the magnetic flux through the ring?
What emf is induced in the ring?
What is the direction of the induced current of the ring? A metal ring with resistance of .24 ohms and diameter 18cm is rotating at a constant rate of 12 Hz in a uniform magnetic field with constant magnitude 1.2mT. The ring rotates counter clock wise. The area vector of the ring initially points out of the page, in the same direction of the magnetic field but changes as the ring rotates.
At this moment what is the magnetic flux through the ring?
What emf is induced in the ring?
What is the direction of the induced current of the ring?
At this moment what is the magnetic flux through the ring?
What emf is induced in the ring?
What is the direction of the induced current of the ring?
Explanation / Answer
Area of the loop, A = pi*d^2/4
= pi*0.18^2/4
= 0.0254 m^2
angular frequency, w = 2*pi*f
= 2*pi*12
= 75.36 rad.s
B = 1.2*10^-3 T
R = 0.24 ohms
a) magnetic flux through the loop = A*B
= 0.0254*1.2*10^-3
= 3.048*10^-5 T.m^2
b) induced emf in the ring = A*B*w
= 0.0254*1.2*10^-3*75.36
= 2.3*10^-3 volts
c) induced current = emduced emf/R
= 2.3*10^-3/0.24
= 9.58*10^-3 A or 9.58 mA