An electrical discharge excites the He atom from its ground state (arbitrarily assigned the energy E1 = 0) to its excited state of 20.61 eV. The excited He atom collides with a Ne atom in its ground state and excites this atom to the state at 20.66eV. Neon atoms make a variety of downward transitions in falling from the E4* down eventually to level E1. This laser can produce a green or a red laser beam. From the data in the figure, (a) what is the wavelength of the red He–Ne laserlight? And (b) If the green light has a wavelength of 543 nm, what is the energy E2?