Instruments: [Daily Question] April 25, 2011

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This post was last edited by cnooczhouyx on 2011-4-27 at 10:00. [Daily Question] Question for April 25, 2011: 1. A key parameter of radioactivity is the half-life, which is the time it takes for (　　). A. Half of the distance traveled by the rays B. The intensity decreases by half C. The radiation source loses half of its strength D. The measured value returns to half of its original value. 2. When the level measured by a radioactive level gauge is at its highest, the gauge’s indication is also at its highest. Which of the following statements is correct? (　　) A. The strongest rays are received by the probe. B. The weakest rays are received by the probe. C. The probe receives no rays at all. D. The rays received by the probe depend on the instrument. Note: 1) The top 50 participants will definitely receive a reward; in principle, no additional points are given for those beyond 50. Among them, the first 20 who answer correctly receive a ‘Wealth 5’ award, while those from 21 to 50 receive a participation award. Those who answer 3 questions correctly and 2 incorrectly receive a ‘Wealth’ award ； Points may be awarded additionally for detailed analysis, in-depth discussion, and discretion ； 2) Please hide your replies; the method for doing this is at http://bbs.hcbbs.com/thread-492556-1-1.html. Do not edit the replies after posting them. (No rewards will be given for any replies that are not hidden. ) 3) Posts that expire will be closed, and the answers will become visible after the post is closed ； Thank you all for your participation ； 【Daily Question】Answer for April 25, 2011: 1. B 2. B.