Intensity (I) and Reference Intensity (Iref)

Intensity (I) and Reference Intensity (I_ref)

Exercise 1-3:

Sound Intensity Level (SIL) and Sound Pressure Level (SPL) in decibels (dB);
Intensity (I) and Reference Intensity (I_ref)

Excess pressure – root-mean-squared p_rms, Sound velocity (c) and Ambient density ρ_A

Exercise 1: If the acoustic pressure is doubled, the sound pressure level is increased with how many dB?                                                                                                                            

Workings:[unique_solution]

Answer:

Exercise 2: The sound pressure level at the threshold of pain for humans hearing sound waves in air is 130 dB re 20 μPa. By assigning (and presenting) typical properties for air, calculate the intensity of sound at this threshold.                                                                        

Workings:

Answer:

Exercise 3: Take 2 harmonic plane waves in both air and water. Intensities are identical. The sound pressure level of the sound wave in air = 120 dB re 20 μPa. By assigning (and presenting) typical properties for air and water, calculate the sound pressure level of this wave in water.                                                                                                                              

Workings:

Answer: