Struggling with this homework question please help! Anything will help please. T
ID: 3163324 • Letter: S
Question
Struggling with this homework question please help! Anything will help please.
Two (semi)infinite grounded conducting plates meet at an angle of 90 at the origin. A point charge q is a distance r0 from the origin along their angular bisector.
(a) What image charges are needed to satisfy the boundary conditions and model these grounded plates as a collection of point charges? Specify location, magnitude, and sign.
(b) Use multipole expansion to determine the dominant r dependence of the potential along the angular bisector, for r r0. (Hint: Choose an orientation with the real charge on the horizontal axis.)
(c) What image charges would be needed to satisfy the boundary conditions and model these grounded plates as a collection of point charges if the angle between the conducting plates was 60 ? Specify location, magnitude, and sign.
(d) Use multipole expansion to determine the dominant r dependence of the potential along the angular bisector for this 60 configuration (r>>r0).
Explanation / Answer
To begin with, assume the semi-infinite grounded plates to be extended to infinity. Now the plates will divide the space into 4 quadrants. The given charge is positive lies on the angle bisector at a distance r0, to solve this problem 3 charges will have to be introduced, 2 negative and 1 positive. The first negative charge will be in the quadrant to the left of the given positive charge at a distance of r0 on the respective quadrants angle bisector. The second positive charge will be a distance 2r0 from the original positive charge in the diagonal quadrant on the anglbisectoror again. The final negative charge will be placed in the remaining quadrant similarly.