## Essential University Physics: Volume 1 (3rd Edition)

We set the two equations for the intensity of light equal to each other in order to find the distance at which the two lights have the same intensity: $r_{4.9} = r_{9.2}\sqrt{\frac{P_{4.9}}{P_{9.2}}} =1.9\sqrt{\frac{4.9}{9.2}} = 1.4 \ m$