1. What is the wavelength (in nm) of a photon required to excite an electron from n = 2 to n = 3 in a He ion? Submit an answer to three significant figures.

2. A laser pointer used in the classroom emits light at 5950 , at a power of 4.00 mW. (One watt is the SI unit of power, the measure of energy per unit of time. 1 W = 1 J/s). How many photons are emitted from the pointer in 115 seconds?