Physics 112 HW10
Due Wednesday, 1 October 2014
U3-VfEI07. A spherical conducting shell has an inner radius of 3 cm and an outer radius of 5 cm. It carries a total charge of 3 nC. A second, larger spherical conducting shell has an inner radius of 8 cm and an outer radius of 10 cm. It carries a total charge of -5 nC, and is concentric with the first (the first is inside the second). Assuming that the electric potential goes to zero as we get very far away from the concentric shells, find and graph the electric potential as a function of distance r from their common center (all r > 0).
U3-VfEI05. A long coaxial cable consists of a 2.0-mm-diameter inner conductor and an outer conductor of diameter 1.6 cm and negligible thickness (see Fig. 22.22 in text). If the inner and outer conductor have effective linear charge densities of -56 nC/m and +56 nC/m, respectively, what is the magnitude of the potential difference between them?
U3-VfEI06. Two conducting spheres are isolated from each other and other charges. The larger sphere has a radius of 30 cm, while the smaller sphere has a radius of 1 mm. They are both charged up to a voltage of +500V (with respect to ground, which is V = 0 as r ® ¥). Determine the surface charge density (in C/m2) of each sphere. Which one has the greater surface charge density?
U3-EfV01. (Wolfson, Ch. 22 Problem 30) The figure at right shows some equipotentials in the x-y plane.
a) In what region is the electric field the strongest?
b) What is the direction of the field where it is the strongest?
c) What is the magnitude of the field where it is the strongest?
U3-EfV02. For the situation below, the black areas are conductive like the tape and ink in our equipotential lines lab. Sketch four equipotential lines between these two conductive shapes if there is a 12 volt potential difference between them. Also sketch the electric field lines.
(over)