Suppose that the sound level of a conversation is initially at an angry 74 dB and then drops to a soothing 53 dB. Assuming that the frequency of the sound is 523 Hz, determine the (a) initial and (b) final sound intensities and the (c) initial and (d) final sound wave amplitudes. Assume the speed of sound is 344 m/s and the air density is 1.21 kg/m3.