/(W·m-2) 痛觉阈 10 音乐 10 10 语育 10 0-10 可闻阈 10030010003000100020/Hz
几种声音近似的声强、声强级和响度 声源 声强Wm2声强级dB响度 引起痛觉的声音 120 钻岩机或铆钉机 102 100 震耳 交通繁忙的街道 105 70 响 通常的谈话 106 60 正常 耳语 10-10 20 轻 树叶的沙沙声 10-11 10 极轻 引起听觉的最弱声音1012
声源 声强W/m2 声强级dB 响度 引起痛觉的声音 1 120 钻岩机或铆钉机 10-2 100 震耳 交通繁忙的街道 10-5 70 响 通常的谈话 10-6 60 正常 耳语 10-10 20 轻 树叶的沙沙声 10-11 10 极轻 引起听觉的最弱声音 10-12 0 几种声音近似的声强、声强级和响度
Sample problem 19-2 Spherical sound waves are emitted uniformly in all directions from a point source, the radiated power P being 25 w. What are the intensity and the sound level of the sound wave at a distance r=2. 5m from the source? Solution 251 =0.32w/m 4m24x(2.5m) Sz=1010g/ 0.32v/m =10 log 115dB 102w/m
Sample problem 19-2 Spherical sound waves are emitted uniformly in all directions from a point source, the radiated power P being 25 w. What are the intensity and the sound level of the sound wave at a distance r=2.5m from the source? Solution: 2 2 2 0.32 / 4 (2.5 ) 25 4 w m m w r P I = = = dB w m w m I I SL 115 10 / 0.32 / 10log 10log 1 2 2 2 0 = = = −