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2. A helium-ncon laser a = 633 nm) is built with a glass tube of inside diameter 1.0 mm, as shown below. One mirror is partially transmitting to allow the laser beam out. An electrical discharge in the tube causes it to glow like a neon light. From an optical perspective, the laser beam is a light wave that diffexets out through a 10-mm-diameter circular opening The output power of the laser is 1.5 mW. Mirror Laser Discharge 1.0 mm beam Electrodes Partial mirror Power supply a Can a laser beam be perfectly parallel, with no spreading? Make sure to explain your rcasoning b. The angle 0, to the first minimum is called the divergence angle of a laser beam Calculate the divergence angle of this laser beam. c Calculate the diameter (in mm) of the laser beam after it travels 4.9 m. Note: The wave model is appropriate because, at this distance, the spreading due to diffraction is significantly larger than the size of the opening d. Assuming no loss of power, calculate the intensity at this distance. e Calculate the diameter of the laser beam after it travels 1.3 km, F. Assuming no loss of power, calculate the intensity at this distance. g If the Moon is directly above you, calculate the diameter of the laser beam on the surface of the Moon h. Assuming no loss of power, calculate the intensity of the light on the surface of the One 633 nm photon has an energy of 196 eV. Calculate the number of photons from the laser beam entering the pupil of an eye (radius of 2 mm) of a person on the Moon Moon. 1