Use the needle from your lab kit and a plate or other hard object. Move to the quietest place you can nd. Measurements of sound or changes of sound, called signals, always have an ambient, always present level of sound even when there is no signal. This ambient level is called the background and often has the characteristics of noise. 1. What is the background sound intensity? dB W/m51 2. How much larger is this compared to the "threshold of hearing" (0 dB). Express your answer as a multiple of 10'12 W/mz, i.e. times the threshold of hearing