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