A single panel of gypsum board 25 mm thick with dimension 3.3m x 3.3m is installed in a transmission loss test facility between two reverberation chambers. The average sound pressure level in the source room reverberation chamber is 100 dB in the 500 Hz one-third octave band. The T60 value in the 500 Hz one-third octave band in the receiver room was measured to be 1.4 seconds, the surface area of the receiver room is 200 me and the volume is 180 m3 . The density of air is p = 1.21 kg/m, and the speed of sound in air is c = 343 m/s. Assume that the properties of the gypsum board are: . Young's Modulus 2.159 Pa . Density 760 kg / m3 . VE/p =1670 m/s . Loss factor 0.01 . Poisson's ratio 0.25 A. What is the first panel resonance frequency ? Number Hz [ Your answer should be accurate to within +/- 5% ] B. What is the critical frequency of the panel ? fc = Number Hz [ Your answer should be accurate to within +/- 5% ] C. What is the predicted transmission loss of the panel for the 500 Hz octave band? TL = Number dB [ Your answer should be accurate to within +/- 1 dB ] D. What is the expected space average sound pressure level in the receiver reverberation chamber if the sound pressure level in the source room is 105 da re 20 micro-Pa ? Lp = Number dB re 20 micro-Pa [ Your answer should be accurate to within +/- 1 dB ]