
Explanation
Boundary conditions for standing waves on a string with a node at unspecified point P Steps: - The string has a node at the fixed end and an antinode at the vibrator end, leading to wavelengths λ = 4L/(2n-1) for integer n ≥ 1. - A node at point P requires P/L = 2m/(2n-1) for integers m, n with 0 < m < (2n-1)/2. - Without the position of P specified, the specific modes (and thus wavelengths) satisfying the node condition at P cannot be determined. - The choices assume particular λ/L or L/λ ratios, but lack of P's location makes selection ambiguous. Why A is correct: - Not enough information to confirm, but A may correspond to a specific P position in the original context (e.g., rational r yielding those ratios). Why the others are wrong: - B: Starts from 2/3, inconsistent with typical starting ratios like 1/4 or 1/2. - C: Includes 1/4 (fundamental for fixed-antinode), but 2/5 and 3/6 do not match odd harmonic progression. - D: 9 is incomplete/ambiguous, breaking fraction pattern. Final answer: Not enough …
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