A sound wave with amplitude xo is measured by an observer to have an intensity of I0 when the observer is standing 4.0 meters from the source. Which best describes the amplitude of a sound wave and distance from the source where it will be measured with an intensity of 16Io? Increase the amplitude to 8xo and stand 2 meters from the source. Increase the amplitude to 4xo and stand 10 meters from the source. Increase the amplitude to 2xo and stand 2 meters from the source. Increase the amplitude to 4xo and stand 8 meters from the source.