A. 0.95m
B. 0.60m
C. 0.50m
D. 0.45m

Correct Answer:

Option D – 0.45m

Explanation

In vibration in a closed pipe/tube, the first resonance occurs at a position L = V/4f,
when reading from the top of the tube,

L1 = _340
4 x 340

= 0.25m
L2 = 3V/4f

L2 = 3 x 340
4 x 340

= 0.75m
L3 = 5V/4f

L3 = 5 x 340
4 x 340

= 1.25m
However, the effective length of the tube is 1.2m. Thus reading from below, the first position of resonance will be 1.20 – 0.75m = 0.45m

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