Unless indicated otherwise, assume the speed of sound in air to be v = 344 m/s. Example 16.1 (Section 16.1) showed that for sound waves in air with frequency 1000 Hz, a displacement amplitude of 1.2 X 10-8 m produces a pressure amplitude of 3.0 X 10-2 Pa. Water at 20o C has a bulk modulus of 2.2 X 109 Pa, and the speed of sound in water at this temperature is 1480 m/s. For 1000-Hz sound waves in 20o C water, what displacement amplitude is produced if the pressure amplitude is 3.0 X 10-2 Pa? Explain why your answer is much less than 1.2 X 10-8 m.
Solution 2E Step 1 of 3: We know that 2 k = and v = f k = 2f v Step 2 of 3: We have relation pmax = BkA Substitute k in the above equation p = 2fBA max v pmax A = 2Bf 2 = 3×10 ×1480 2×2.2×10 ×1000 12 =3.21 × 10 m