Question

An electric dipole antenna used to transmit radio waves is oriented vertically.At a point due north of the transmitter, how should a magnetic dipole antenna be oriented to serve as a receiver?

Short answer

Answer: The magnetic dipole antenna should be oriented east-west, with its magnetic field horizontal.

Step-by-step solution

Understanding electric dipole antenna and magnetic dipole antenna

Electric dipole antennas and magnetic dipole antennas are used to transmit and receive electromagnetic waves, such as radio waves. The electric dipole antenna works by generating an electric field, while the magnetic dipole antenna works by generating a magnetic field. When one antenna transmits a signal, the other can receive it if oriented correctly.

Understanding the electric field generated by the electric dipole antenna

The electric dipole antenna in this problem is oriented vertically. This means that the electric field generated by the antenna will be in the vertical direction, perpendicular to the ground.

Understanding the magnetic field generated by the magnetic dipole antenna

When receiving a signal from an electric field, a magnetic dipole antenna will be most efficient when its axis is perpendicular to the plane of the electric field. Since the electric field generated by the electric dipole antenna is vertical, we need the magnetic dipole antenna to be oriented such that its magnetic field is horizontal.

Determining the optimal orientation for the magnetic dipole antenna

To maximize the received signal from the electric dipole antenna, the magnetic dipole antenna should be oriented in a way that its magnetic field is horizontal and perpendicular to both the electric field and the direction from the transmitter to the receiver. Since the electric field is vertical and the receiver is due north of the transmitter, the optimal orientation of the magnetic dipole antenna must be east-west.

Answer

To serve as a receiver, at a point due north of the transmitter, the magnetic dipole antenna should be oriented east-west, with its magnetic field horizontal.