In the far field, as distance increases, the beam tends to become more what?

In the far field, as distance increases, the beam tends to become more what?

• A. Becomes more uniform
• B. Becomes more divergent
• C. Becomes more absorbed
• D. Becomes more energetic

Answer: (A)

In the far field, waves behave more like a plane wave with almost flat wavefronts. When distance increases, the contributions from different parts of the source spread out and interfere in such a way that the energy across the beam’s cross-section averages out, giving a more uniform distribution. Near the source, the beam can have hot spots and irregular intensity due to complex interference patterns, but those fluctuations smooth out as you move farther away. This uniformity is about the cross-sectional energy profile, not about energy increasing or the beam being absorbed; the beam does spread, but the profile becomes more even.

In the far field, waves behave more like a plane wave with almost flat wavefronts. When distance increases, the contributions from different parts of the source spread out and interfere in such a way that the energy across the beam’s cross-section averages out, giving a more uniform distribution. Near the source, the beam can have hot spots and irregular intensity due to complex interference patterns, but those fluctuations smooth out as you move farther away. This uniformity is about the cross-sectional energy profile, not about energy increasing or the beam being absorbed; the beam does spread, but the profile becomes more even.