Container and Storage Devices Section: [Daily Question] 2011.05.09

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Last edited by Shenlan Yipan on 2011-5-9 09:43. Multiple-choice question: 1. When light is incident perpendicularly, if Z1 > Z2 – referring to the steel/water interface at the bottom of the workpiece during underwater flaw detection – then what is the sound pressure reflection coefficient at the steel/water interface? (A) 4 Z1×Z2 / (Z1 + Z2)² (B) 2 Z2 / (Z1 + Z2) (C) (Z2 – Z1) / (Z1 + Z2) (D) [(Z2 – Z1) / (Z1 + Z2)]². For normal incidence, if Z1 < Z2 – that is, at the water/steel interface on the upper surface of the workpiece during water immersion testing of steel – then the sound pressure reflection coefficient at the water/steel interface is (). (A) –0.937 (B) 0.937 (C) 1.937 (D) 0.063 Answer: C B 1: Those who participate and answer correctly will be rewarded, with the maximum number of points awarded being 50. Reply ； 2: Please hide your replies. The method for hiding them is: http://bbs.hcbbs.com/thread-492556-1-1.html. Those who do not hide their replies or edit them after posting will not be awarded a reward ； 3: Please actively provide one question per day at http://bbs.hcbbs.com/thread-781748-1-1.html