InterviewSolution
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InterviewSolution
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A well with vertical side and water at the bottom resonates at 3 Hz and at no other lower frequency. The air in the well has density 1.10 kg m-3 and bulk modulus of 1.32 x 105 Nm-2 Nm, then the depth of well is(a) 30 m(b) 29 m(c) 25 m(d) 32 m |
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Answer» Answer is : (b) 29 m For air, \(\rho\) = 1.10 kgm-3 K = 1.32 x 105 Nm-2 Speed of sound in air, v = \(\sqrt{\frac{K}{\rho}}\) \(\sqrt{\frac{1.32\times 10^5}{1.10}}\) = 3.46 x 102 = 346 ms-1 It is similar to a closed organ pipe, hence fundamental frequency of well is v = \(\frac{v}{4L}=\frac{346}{4\times L}\) \(\Rightarrow L=\frac{346}{4\times 3}\) = 29 m |
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