Question

A metal disc of radius R rotates with angular velocity Omega (w) about an axis perpendicular to its plane passing through its centre in a magnetic field B acting perpendicular to the plane of the disc calculate the induced EMF between the rim and the axis of the disc

Answer 1

speed of any length dr on the disk=Omega*r

E= -BA/t so applying here

B given
dA/dt= dr*dAngle/dt
=dr*rw

E=-B wr dr
Etotal=INT Bwrdr over r=0 to R
Etotal=BWR^2/2

check that

Answer 2

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