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Use the 鈥渄uality鈥 transformation of Prob. 7.64, together with the fields of an oscillating electric dipole (Eqs. 11.18 and 11.19), to determine the fields that would be produced by an oscillating 鈥淕ilbert鈥 magnetic dipole (composed of equal and opposite magnetic charges, instead of an electric current loop). Compare Eqs. 11.36 and 11.37, and comment on the result.

Short Answer

Expert verified

The fields that would be produced by an oscillating 鈥淕ilbert鈥 magnetic dipole isE'=0m024csinrcost-rc^ and B'=0m024c2sinrcosct-rc^, and the equations 11.36 and 11.37 are identical to the fields of an ampere dipole.

Step by step solution

01

Expression for the duality transformation equations:

Write the expression for the duality transformation equations.

E'=Ecos+cBsincB'=cBcos-Esincqe'=cqecos+qmsinqm'=qmcos-cqesin

02

Determine the electric field produced by an oscillating “Gilbert” magnetic dipole:

Substitute =90in all the duality transformation equations.

  • First equation:

E'=Ecos90+cBsin90E'=cB........(1)

  • Second equation:

cB'=cBcos90-Esin90cB'=-E.......(2)

  • Third equation:

cqe'=cqecos90+qmsin90cqe'=qm

  • Fourth equation:

qm'=qmcos90-cqesin90qn'=-cqe

Write the expression for the magnetic field using the equation .

B=-0p024csinrcost-rc^

Here,p0=-m0c .

Hence, the above equation becomes,

B=-0m024c2sinrcost-rc^

Substitute B=-0m024c2sinrcost-rc^in equation (1).

E'=c-0m024c2sinrcost-rc^E'=0m024csinrcost-rc^

03

Determine the magnetic field produced by an oscillating “Gilbert” magnetic dipole:

Write the expression for an electric field using the equation .

E=0m024csinrcost-rc^

Substitute E=0m024csinrcost-rc^in equation (2).

B'=1c-0m024csinrcost-rc^B'=-0m024c2sinrcosct-rc^

Hence, these are identical to the fields of an ampere dipole.

Therefore, the fields that would be produced by an oscillating 鈥淕ilbert鈥 magnetic dipole isE'=0m024csinrcost-rc^ andB'=-0m024c2sinrcosct-rc^ and the equations 11.36 and 11.37 are identical to the fields of an ampere dipole.

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