180° Phase Difference in Transverse Waves

Steps:

• Locate point X and note its displacement (e.g., at crest, maximum upward).
• Recall that 180° phase difference means opposite displacement (e.g., trough if X is crest) or half-wavelength separation.
• Examine diagram positions: crests/troughs indicate phase opposition.
• Select option showing exact opposite displacement to X.

Why A is correct:

• Point A is at a trough while X is at a crest, matching the definition of 180° phase shift where displacements are equal in magnitude but opposite in direction.

Why the others are wrong:

• B: Same displacement direction as X (both crests), indicating 0° phase difference.
• C: Partial displacement (e.g., on rising slope), showing 90° phase difference.
• D: Similar to X or 360° equivalent, not opposite phase.

Final answer: A