1. The problem statement, all variables and given/known data An electric charge q is uniformly dispersed over a surface of elliptical tube with major and minor axis a and b. What is the surface charge density? 2. Relevant equations 3. The attempt at a solution I I know that you have to cut the tube in to thin ellipses and calculate a linear charge density for an ellipse. Than you sum the thin ellipses together to get a surface charge density of a tube. But I do not know how to calculate a linear charge density of an ellipse.