Ultrasound loudness Assuming no absorption, what is the change in sound intensity level, in dB, in...

 

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Ultrasound loudness Assuming no absorption, what is the change in sound intensity level, in dB, in travelling from a position 1.0 cm from a small ultrasound source, to a position 9.0 cm from the source. Assume this to be a point source that emits ultrasound waves equally in all forward directions and give thought to the sign of your answer. Solving: (2A/² STRAN SA₂ SA₁ 2 Surface area, A = r² where we define SA for a sphere = 47r² and A for any cone x r². So, A₂/A₁ = r2/r2. Note also, I x P/A so 1₂/1₁ = r²/r² Ans. -19 dB as a 'solid angle". 13:50 Ultrasound loudness Assuming no absorption, what is the change in sound intensity level, in dB, in travelling from a position 1.0 cm from a small ultrasound source, to a position 9.0 cm from the source. Assume this to be a point source that emits ultrasound waves equally in all forward directions and give thought to the sign of your answer. Solving: (2A/² STRAN SA₂ SA₁ 2 Surface area, A = r² where we define SA for a sphere = 47r² and A for any cone x r². So, A₂/A₁ = r2/r2. Note also, I x P/A so 1₂/1₁ = r²/r² Ans. -19 dB as a 'solid angle". 13:50

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We know that I2I1 r1r22 I2I1 192 181 I1 81I2 Now we also know that Sound level L ... View the full answer