1. The problem statement, all variables and given/known data Suppose I use visible (say yellow) light to observe an electron. Roughly speaking, I will then be able to localize the electron to a region about the size of the wavelength of the light. According to the uncertainty principle, I am now limited as to how well I know the momentum of the electron. If the maximum momentum that the electron can have is roughly equal to the uncertainty of the momentum, about how long will I have to wait so that the electron could be anyplace in the City of Ann Arbor? To do this, you will need to estimate the size of Ann Arbor, and calculate how long it would take the electron to go a distance about that size. 2. Relevant equations I chose D = Rt and A = pi(R^2) 3. The attempt at a solution I just decided to use an area equation, pretending Ann Arbor is a circular town, using a given area of 27 miles. Then I just used D = rt to find the time it would take the electron to go that distance, not completely sure if that was the right thing to do. I used c as the speed assuming the electron goes that speed.... Is that maybe where my problem is wrong? my answer was t = 3.15 x 10^(-5) seconds. Please help, this is killing meeeeeee!