1Phys 1240: Sound and MusicLAST: decibelsTODAY: decibels and hearingNEXT: sound and hearingREAD: 6.6 (mostly, try to makesense of Fig 6.12!)CAPA 5 due tonight.Exam 2 is next Thursday.5.2.3bThere are two instruments, a trumpet anda flute. The trumpet produces a soundwith100x more intensity than that of theflute.The SIL (decibel level) for the trumpetis…compared to the flute.a) 2 dB greaterb) 10 dB greaterc) 20 dB greaterd) 100 dB greatere) Other/Not enough information/???Decibels as "relative SIL’s"100 dB50 dB30 dB20 dB10 dB0 dBDifference inSIL1010100,000=1051,000100101Ratio ofintensities5.2.5If a sound is 0 dB, is any energytransferred?a) Yesb) Noc) ??2…10…10 dB3 dB2 dB1 dB0 dBDiff in SIL1Intensity ratio(etc - see Table 5.1 in text)…10…10 dB3 dB2 dB1 dB0 dBDiff in SIL21.61.26 (call it 1.3)1Intensity ratio(etc - see Table 5.1 in text)5.2.4bA trumpet produces a sound 2x moreintense than the flute.Compared to the SIL (“decibel level”) ofthe flute, the decibel level of the trumpetis…A) 1.6 dB louderB) 2 dB louderC) 3 dB louderD) 20 dB louderE) You can’t answer unless I tell youhow many dB the flute is!5.2.4biiA flute plays at 60 dB.A trumpet produces a sound 2x moreintense than the flute.The decibel level of the trumpet is…A) 120 dBB) 2 dBC) 80 dBD) 62 dBE) 63 dB35.2.4bA trumpet is 20x more intense than aflute.How many decibels louder is thetrumpet?A) 3 dB higherB) 12 dB higherC) 13 dB higherD) 20 dB higherE) 23 dB higher5.2.4cA trumpet is 22 dB more than the flute.The ratio of intensities, I(trumpet)/I(flute), is…A) 16B) 22C) about 30D) 160E) 2005.2.4dA violin is playing at 55 dB. If you add asecond violin, what happens to the SIL?A) Stays the same, still 55 dBB) Goes to 57 dBC) Goes to 58 dBD) Goes to 75 dBE) Goes to 110 dB5.2.4eA violin is playing at 60 dB. Whathappens to the SIL if there are 20violins playing?A) Goes to 73 dBB) Goes to 76 dBC) Goes to 80 dBD) Goes to 120 dBE) Goes to much more than 120
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