What would be the difference in intensity from a 176 dB sound and a 136 dB sound

Question

What would be the difference in intensity from a 176 dB sound and a 136 dB sound?
A. 10 Times B. 40 Times C. 100 Times Passage I The results of Kinsler and Frey initial intensity, lo, when it is reflected in perpendicular incidence, is given by the formula: On an oscilloscope it is the reflected wave that is picked up and displayed on the graph. 1962, revealed that the intensity (reflected), I, from a beam of 1C-P22) o(p1c1+P22) where the p's are the respective densities of the two media and the c's are the respective velocities of sound in the two media. Typical values for humans are given in the table below. It is seen from the table that bone gives such a high reflectivity when next to any other tissue that one ot "see" beyond it. Thus in tissue scanning or echocardiography the transducer can only be placed between ribs, on the neck aiming into the thorax, or on the abdominal region. During examination of internal organs by methods such as echocardiography, sufficient power is required to obtain a reflection signal well above the noise level. The requirements determined experimentally, are shown in Table 2 below. These values are well into the discomfort and damage levels to tissues. However, there is no reason for continuous operation at such high frequencies to observe a slowly moving mass. Therefore the operation is one of pulsing. Typical values are about 200 pulses per second with a pulse duration of 5 x 10 seconds. Thus the total transmission time is 200 x 5 x 106 seconds and the power dissipation in the body is only .08 w/cm2 at 1 x 106 Hz which is within the safety region. (log 4·.6, Intensity = Power divided by 4 r)) Table One p (gm/cm) Tissue Blood Fat Sound velocity (m/sec) 1560 1470 1568 0.928 1.058 1.85 Muscle Bone (skull) 3360

Explanation / Answer

D. 10,000 Times  

I1 = 176 dB = 398107 W/m^2

I2 = 136 dB = 39 W/m^2

I1/I2 = 398107/39 = 10000 times

Hence, I1 = 10000 I2

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