Question

The wave reaching the receiving antenna will have maximum intensity, if the direct wave and wave after reflection from the Earth's surface

• A. are out of phase by ${90}^{\circ }$.
• B. are out of phase by ${270}^{\circ }$.
• C. are in phase.
• D. None of the above.

Answer 1

Answer: (C)

are in phase.

If the direct wave and reflected (from Earth's surface) wave are in phase, i.e., the path difference (between these waves is $\lambda$), then they interfere constructively and thus resultant wave obtained at the receiver's end is maximum.