Which of the following situations will cause diffraction of a $wave$?

• A. A light $wave$ travels in a straight line through empty space.
• B. A water $wave$ moves across a deep, unobstructed pool.
• C. A radio $wave$ is absorbed by a metal sheet.
• D. A sound $wave$ passes through a narrow doorway.

Answer: (D)

Verified step by step guidance

1. Understand the concept of diffraction: Diffraction occurs when a wave encounters an obstacle or a slit that is comparable in size to its wavelength, causing the wave to bend around the edges or spread out after passing through the opening.
2. Analyze each situation to see if the wave encounters an obstacle or opening that can cause bending or spreading:
3. 1. A light wave traveling in a straight line through empty space does not encounter any obstacle or slit, so no diffraction occurs.
4. 2. A water wave moving across a deep, unobstructed pool also does not encounter any obstacle or slit, so no diffraction occurs.
5. 3. A radio wave absorbed by a metal sheet is stopped rather than bent or spread, so diffraction does not occur here.
6. 4. A sound wave passing through a narrow doorway encounters an opening comparable to its wavelength, causing the wave to bend and spread out, which is diffraction.