How does diffraction affect the propagation of a wireless signal?

• A. It allows the signal to bend around obstacles and reach areas that are not in the direct line of sight.
• B. It increases the frequency $f$ of the wireless signal as it passes by obstacles.
• C. It causes the wireless signal to travel only in straight lines without any deviation.
• D. It causes the signal to be completely blocked by obstacles, preventing any transmission beyond them.

Answer: (A)

Verified step by step guidance

1. Understand that diffraction is a wave phenomenon where waves bend around obstacles or spread out after passing through small openings.
2. Recognize that wireless signals are electromagnetic waves, which can exhibit diffraction when encountering obstacles such as buildings or hills.
3. Note that diffraction allows the wireless signal to bend around these obstacles, enabling the signal to reach areas that are not in the direct line of sight of the transmitter.
4. Contrast this with the idea that signals traveling only in straight lines would be blocked by obstacles, which is not the case due to diffraction.
5. Conclude that diffraction does not increase the frequency of the signal nor completely block it, but rather helps in signal propagation beyond obstacles.