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Electromagnetic Waves — Physics STD 12 Science — Question

Bihar BoardEnglish MediumSTD 12 SciencePhysicsElectromagnetic Waves1 Mark
MCQ
A magnetic field can be produced by:
  • A
    A moving charge.
  • B
    A changing electric field.
  • C
    Neither of them.
  • D
    Both of them.
✓

Answer

  1. Both of them.

Explanation:

According to Ampere-Maxwell's Law, a magnetic field is produced due to the conduction current in a conductor and the displacement current. The conduction current is actually the motion of the charge. The displacement current is due to the changing electric field. The displacement current is given by,

$\text{i}_\text{d}=\in_0\frac{\text{d}\phi_\text{E}}{\text{dt}}$ $\big(\because\phi_\text{E}$ is the electric flux$\big)$

Thus, the magnetic field is produced by the moving charge as well as the electric field.

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