33C Moon-Earth distance Eq. (33.31) Because of diffraction, the beam spreads by a total angle 20...
33C Moon-Earth distance Eq. (33.31) Because of diffraction, the beam spreads by a total angle 20 When the beam reaches the earth, it has spread out into a circle of diameter w. Mirror on moon 24 L Rellected beam returning to earth To measure the Moon-Earth distance, a laser is beamed from Earth to the Moon. A mirror array placed on the Moon reflects the laser back to Earth. Diffraction occurs. The laser wavelength is 532 nm, and beam diameter from Earth is 50 cm. a) Find the width in km of the central maximum on the Moon. Each mirror in the array is only 4 cm diameter. Most laser power is wasted. b) Find the width in km of the central maximum reflected back to Earth.