Question

An AM radio wave is emitted by a radio antenna and travels across flat ground. Find out the direction of the magnetic field component of the wave?

• A. Parallel to the ground and perpendicular to the direction of propagation
• B. Perpendicular to the ground and to the direction of propagation
• C. Parallel to the ground and to the direction of propagation
• D. Perpendicular to the ground and parallel to the direction of propagation
• E. Parallel to the electric field component of the wave

Answer 1

Answer: (A)

Parallel to the ground and perpendicular to the direction of propagation

According to Maxwell an accelerated charge produces a sinusoidal time varying magnetic field which in turn produces a time varying electric field .The two fields so produced are mutually perpendicular to each other and constitute an electromagnetic wave and propagate in space in the direction perpendicular to both the fields.

An AM wave is also an electromagnetic wave therefore its magnetic field component would be parallel to ground and perpendicular to the direction of propogation.