Which medium effect causes a change in direction of a radio wave typically due to encountering an obstacle?

Which medium effect causes a change in direction of a radio wave typically due to encountering an obstacle?

• A. Reflection
• B. Diffraction
• C. Attenuation
• D. Refraction

Answer: (B)

Diffraction is the bending and spreading of waves as they encounter an obstacle or pass through a gap. For radio waves, this means the wave can bend around edges like buildings or hills and continue propagating into areas not in direct line of sight. This kind of direction change happens specifically because the wave interacts with the obstacle and spreads, unlike reflection (bouncing off a surface) or refraction (changing direction when entering a different medium and usually not due to an obstacle’s edge). Attenuation describes loss of strength, not a change in direction. The amount of bending depends on how large the obstacle is compared to the wavelength; radio waves with wavelengths that can “see” around edges readily diffract, allowing signals to reach around corners and through gaps.

Diffraction is the bending and spreading of waves as they encounter an obstacle or pass through a gap. For radio waves, this means the wave can bend around edges like buildings or hills and continue propagating into areas not in direct line of sight. This kind of direction change happens specifically because the wave interacts with the obstacle and spreads, unlike reflection (bouncing off a surface) or refraction (changing direction when entering a different medium and usually not due to an obstacle’s edge). Attenuation describes loss of strength, not a change in direction. The amount of bending depends on how large the obstacle is compared to the wavelength; radio waves with wavelengths that can “see” around edges readily diffract, allowing signals to reach around corners and through gaps.