A thin circular disk of radius `R` is uniformly charged with density `sigma gt 0` per unit area.The disk rotates about its axis with a uniform angular speed `omega`.The magnetic moment of the disk is :

Options

A. `piR^(4)sigmaomega`
B. `(piR^(4))/2sigmaomega`
C. `(piR^(4))/4sigmaomega`
D. `2piR^(4)sigmaomega`

Answer

3

Explanation

`q/(2M)"Magnetic dipole moment "/"Angular momentum"`
`therefore "Magnetic dipole moment"(M)`
`M=q/(2M)=((MR^(2))/2)omega=1/4sigma.piR^(4)omega`