(a) the intensity of sound coming from a speaker 2 m away is 80 db. how far away must you stand for the intensity to be reduced to 40 db? (b) the earth has a radius of r = 6.4 106 m. it orbits the sun in a nearly circular orbit at an average distance of 1.5 101m. the solar intensity at the upper atmosphere is 1367 w/m2. how much energy does the sun radiate per second?