354 Image FormationP36.9(a)11 2pqR+=gives130 01240 0..cmcm−qaf40 0130 0008331q=−−−.cmcmcmsoq12 0. cmMqp=−−=12 030 00400...cmcmaf.(b)gives160 040 0cmcm−q40 0160 0006661q−−.cmcmcmsoq15 0Mqp=−−=15 060 00250...cmcmaf.(c)Since M>0 , the images are upright .P36.10With radius 2.50 m, the cylindrical wall is a highly efficient mirror for sound, with focal lengthfR==2125m.In a vertical plane the sound disperses as usual, but that radiated in a horizontal plane isconcentrated in a sound image at distance qfrom the back of the niche, where111pq fso120011m mqq=333m.P36.11(a)becomes60 0190 0qcmcmq=45 0andMqp=−= −
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