InterviewSolution
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InterviewSolution
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Two wires of different densities are soldered together end to end then stretched under tension T. The waves speed in the first wire is twice that in the second wire. (a) If the amplitude of incident wave is A, what are amplitudes of reflected and transmitted waves? (b) Assuming no energy loss in the wire, find the fraction of the incident power that is reflected at the junction and fraction of the same that is transmitted. |
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Answer» Correct Answer - A::B::C `v_2 = (v_1)/2` (a) ` A_r = ((v_2-v_1)/(v_1+v_2))A` `=[((v_1//2)-v_1)/(v_1+(v_1//2))]A` ` = -A/3` `A_t = ((2v_2)/(v_1+v_2))A` `=[(2xx((v_1)/2))/(v_1+((v_1)/2)] A` `= 2/3 A` . (b) Since, reflected waves come in the same medium, we can say that `P prop A^2` `P_r/P_i = (A_r/A_i)^2 = ((-A//3)/A)^2 = 1/9` :. Fraction of power transmitted `=1-1/9 = 8/9`. |
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