Alaser light was shone through a diffraction grating whose lines were 1/1000 mm apart. the distance was measured between the center spot and the first side spot and found to be 99 mm. the distance from the dif‐ fraction grating to the first side spot was found to be 154 mm. calculate the wavelength of light in nm that the laser pointer was emitting

Consider hydrogen in an excited state n = 5n=5 that emits photons to reach the ground state. there are various possible transitions other than straight to the ground state that can occur; for example, it can drop to the n = 3n=3 state followed by the n = 3n=3 to the ground state transition. which of the possible transitions will result in the emission of a photon in the visible region?