Electromagnetism Midterm
"I feel like my brain's burnt." ---Jake Armitage
Just got back from taking my E&M midterm. It wasn't pleasant. It was a 3-4 hour test... in an hour and a half-time slot. The first problem was right out of Jackson, problem 11.15, but with a 2 changed to a 3. Oooh. Took an hour to finish it, but I really never did answer the question for part (b) because I couldn't find an angle for which the situation we were looking for wouldn't occur.
Problem number two was a pair of point charges inside a grounded conducting sphere.
Part (a): Write down the potential in terms of Legendre Polynomials. Took me a minute to realize it wanted me to expand the exact potentials into an approximate series, and then turn *that* into something in terms of Legendre polynomials. Remind me again why using the correct answer is bad, and making it more complicated is good?
Part (b): Find the potential using seperation of variables in spherical coordinates. Not that hard. I just needed another hour to do it.
Part (c): Find surface charge density induced on the sphere by the charges inside. Did this by taking my potential in (a) and lopping off everything except the dipole part.
Part (d): Show that the potential in part (a) reduces to a dipole when the distance between the charges goes to 0. ... I did this in the process of solving for part (c).
Part (e): Replace that nice conductor with a dielectric and find blah blah blah 8 lines of text later I still didn't know what it was asking.
In conclusion: Dr. Moreo, more time plx k bai.
Just got back from taking my E&M midterm. It wasn't pleasant. It was a 3-4 hour test... in an hour and a half-time slot. The first problem was right out of Jackson, problem 11.15, but with a 2 changed to a 3. Oooh. Took an hour to finish it, but I really never did answer the question for part (b) because I couldn't find an angle for which the situation we were looking for wouldn't occur.
Problem number two was a pair of point charges inside a grounded conducting sphere.
Part (a): Write down the potential in terms of Legendre Polynomials. Took me a minute to realize it wanted me to expand the exact potentials into an approximate series, and then turn *that* into something in terms of Legendre polynomials. Remind me again why using the correct answer is bad, and making it more complicated is good?
Part (b): Find the potential using seperation of variables in spherical coordinates. Not that hard. I just needed another hour to do it.
Part (c): Find surface charge density induced on the sphere by the charges inside. Did this by taking my potential in (a) and lopping off everything except the dipole part.
Part (d): Show that the potential in part (a) reduces to a dipole when the distance between the charges goes to 0. ... I did this in the process of solving for part (c).
Part (e): Replace that nice conductor with a dielectric and find blah blah blah 8 lines of text later I still didn't know what it was asking.
In conclusion: Dr. Moreo, more time plx k bai.