1. The problem statement, all variables and given/known data The following is a graph of |(x)|^2 https://www.physicsforums.com/attachment.php?attachmentid=14887&d=1217540634 Question is. What is the probability that an electron will be detected ina 0.0010-cm-wide region at x = 0.50 cm? At x= 0.999 cm? b) If 10^4 electrons are detected, how many are expected to land in the interval -0.30 cm - 0.30 cm. Also, lets suppose that this was a graph for the |(x)|^2 of a neutron. How you you find the value 'a' if it wasn't given? 2. Relevant equations I know that Probability of landing at x = (probability density at x )* (length) Also know that expected value = number of electrons * probability. But I am having trouble putting these two together. Can some please show me how to do this question? 3. The attempt at a solution So I think the probability density at 0.50 cm is 0.5 cm^-1 (reading the graph, the slope is -1 so the y value seems to be 0.5 cm^-1) So P(x) = 0.5 cm^-1* 0.0010 cm = 0.0005? But the answer is 0.005 And I have no idea how to find 'a' by using only the information from the graph. Can someone help me with this whole concept?