Final Exam20492010

# Final Exam20492010 - Final Exam    Name: ...

This preview shows page 1. Sign up to view the full content.

This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Final Exam    Name:  Problem 1      6 charges (+q) are held in a hexagonal  arrangement by some plastic. Each side of  the hexagon has length a.     (a) Calculate the net force (magnitude and  direction) on the charge +Q at the center of  hexagon    (b) Calculate the force (magnitude and  direction) on the charge +Q if the charge  indicated by a red circle is removed.  Problem 2    Consider a uniformly charged sphere of radius R.  The charge density is given by  ρ/m3.     Calculate electric field (magnitude and direction) for  (a) r>R  (b) r<R    Calculate voltage (assuming V=0 at r=infinity) for  (a) r>R  (b) r<R  Problem 3    Calculate the capacitance of a spherical capacitor, which is composed of two spheres  (one inside another), with inner radius a and outer radius b.     Problem 4    Parallel capacitors are half filled by dielectric materials as shown below.  (a)  calculate the capacitances in terms of ε0, A, d. (b) Which capacitor has higher  capacitance?                             Problem 5  At t=0, the switch is closed.     (a) Calculate the current sourced by the  battery at t=0  (b) Calculate the current sourced by the  battery at t=infinity  (c) what is the voltage across the capacitor at  t=infinity  (d) After a long time, the switch is released.   Calculate the current through the capacitor as  a function of time after the switch is released.  Problem 6   Consider a cylindrical wire with radius R with current I flowing through it.  Calculate  magnetic field for   (a) r>R  (b) r<R  assuming that current is uniformly distributed  Problem 7  Consider a coaxial cable as depicted below.  Calculate the inductance per unit length  for the cable if the inside wire has the diameter of a and the outside wire has a  diameter of b.  Problem 8  Find the complex impedance for the parallel RLC circuit as  shown. Assume that we have a voltage source for which we  can adjust the angular frequency ω.  V(t)=Vmaxcos(ωt).    (a) Find the total complex impedance of the circuit  (b) Calculate I(ω).  (c) Find an expression for the phase φ.    (d) Given R=500 ohms, L= 1 henry, C=1.0µF and ω=100  rad/sec. Will the current lag or lead voltage and by how  much?  ...
View Full Document

## This note was uploaded on 07/16/2011 for the course PHY 2049 taught by Professor Saha during the Fall '08 term at University of Central Florida.

Ask a homework question - tutors are online