You are at a rock concert and find that when you stand 10 m from a speaker, the intensit...

You are at a rock concert and find that when you stand 10 m from a speaker, the intensity is so high that it hurts your ears. You decide to move away from the stage so that your ears are more comfortable. If you want to reduce the intensity at your ears by a factor of three, how far from the speaker should you stand? Assume the sound emitted by a speaker at a rock concert has a spherical wave front. How would your answer change if the wave front has the shape of a hemisphere (Fig. P12.37)?