Rarefaction and Wavelength in Sound Wave Pressure Graph

Steps:

• Rarefaction is the point of minimum pressure in the wave, below atmospheric level.
• Examine the graph: point Q marks the lowest pressure, indicating rarefaction.
• Compression is at maximum pressure, so point P represents that instead.
• Wavelength is the distance between two consecutive rarefactions; point X spans one full cycle.

Why C is correct:

• Q identifies the rarefaction per the definition of low-pressure regions in longitudinal waves, and X measures the wavelength as the wave's spatial period.

Why the others are wrong:

• A: P is a compression (high pressure), not rarefaction.
• B: Q is rarefaction, but Y likely marks half-wavelength (compression to rarefaction).
• D: Y does not represent the full wavelength.

Final answer: C