Standing wave oscillation at point Y between nodes

Steps:

• Nodes at P, Q, R have zero displacement; points between oscillate in SHM with amplitude up to 2 cm.
• Stationary wave has antinodes midway between nodes, where displacement varies sinusoidally with time.
• Point X moving down at t=0 implies it's at an antinode or near, starting from positive displacement toward equilibrium.
• Point Y, positioned between nodes (e.g., near an antinode), follows SHM with period matching the wave, starting from a specific phase.

Why A is correct:

• Graph A shows sinusoidal variation starting from positive displacement (upward), matching SHM at Y with max amplitude 2 cm and phase consistent with X's downward motion.

Why the others are wrong:

• B: Starts from zero displacement, incorrect for Y not at node.
• C: Inverted phase, doesn't align with positive upward at t=0.
• D: Damped or irregular motion, violates pure SHM in ideal stationary wave.

Final answer: A