Which is the wrong unit of magnetic dipole moment ?

Options

A. the magnitude of magnetic mometn diminishes
B. the magnetic moment does not change
C. the magnitude of B at (0,0,z) `z gtR` increases
D. the magnitude of B at `(0,0,z) z gt R` is unchanged

Answer

D

Explanation

`tau=MB sin theta therefore M=(tau)/(B)` for max . Sin `theta`
unit of `M=("newton metre")/("tesla")`
unit of M = ampere `m^(2)`
thus (a),(b) and (c ) are correct6
`before (N-m)/("tesla")=("joule")/("tesla") therefore` joule tesla is a wrong unit