Phase difference from displacement-time graph

Steps:

• Identify the period T of the waves from one full cycle on the graph.
• Measure the time delay δt between corresponding points (e.g., zero crossings) on the two curves.
• Calculate phase difference φ = (δt / T) × 360°.
• From the graph, δt corresponds to 135° shift.

Why C is correct:

• Phase difference is defined as the angular shift φ = (2π δt / T) radians or (360° δt / T), matching the graph's 3/8 cycle offset for 135°.

Why the others are wrong:

• A: 45° would be 1/8 cycle, too small for the observed delay.
• B: 90° is 1/4 cycle, underestimating the graph's shift.
• D: 180° is half cycle (out of phase), exceeding the partial overlap shown.

Final answer: C