2.1.1. Two coherent sources, A and B, of radio waves are 40.0 cm apart. Each source emits waves with wavelength 50.0 cm. Consider points along the line between the two sources. At what distances from A, if any, is the interference (a) constructive, (b) destructive? 2.1.2. A coherent source of monochromatic light of unknown wave- length shines on double slits separated by 0.40 mm. Bright spots separated by 0.80 cm appear on a screen 5.0 m away. What is the wavelength of the light?