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A wire of length 2L is made by joining two wires A and b of same lengths but different radii r and 2r and made of the same material. It is vibrating at a frequency such that the joint of the two wires forms a node. If the number of antinodes in wire A is p and that in B is q then the ratio p : q is:(A) 1 : 4 (B) 1 : 2(C) 3 : 5 (D) 4 : 9 |
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Answer» Let MASS per UNIT LENGTH of wires are μ1 and μ2 respectively. ∵ Materials are same, so density ρ is same. ∴μ1=Lρπr2L=μ and μ2=Lρ4πr2L=4μ Tension in both are same =T, let speed of wave in wires are V1 and V2 V1=μT=V.V2=4μT=2V So fundamental frequencies in both wires are f01=2LV1=2LV and f02=2LV2 |
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