PHY 2049: Physics II Tutoring Center is open in room NPB 1215, M-F 12:00AM -4:00PM. It is free. Hopefully all homework problems have been solved. Please see me immediately after the class if there is still an issue.

PHY 2049: Physics II About bicycle riding: If some one shows you a trick, it means that, It is possible to do that trick The person who showed you, can do the trick. It does not mean that you can do the trick. Try it a lot of times and you can too.

PHY 2049: Physics II What have we learned Coulomb’s law, electric field, Gauss’ theorem and electric potential. All comes together in the concept of a capacitor. Capacitor: A device to store charge.

PHY 2049: Physics II

PHY 2049: Physics II Calculate the Electric Field at P Calculate the el. potential at P

PHY 2049: Physics II Point charge Distribution of charges Line charge at an edge Disc on an axis through the center

PHY 2049: Class Quiz If 500 J of work are required to carry a charged particle between two points with a potential difference of 20V, the magnitude of the charge on the particle is: A. 0:040C B. 12:5C C. 20C D. cannot be computed unless the path is given E. none of these

Some old business: What is the electric field of a shell of a uniform spherical charge distribution? What is the potential for each of the above?

PHY 2049: Physics II Some old business The potential of a uniform spherical charge. Calculate electric field, integrate it to get the potential E r R V V

Two particles with charges Q and -Q are fixed at the vertices of an equilateral triangle with sides of length a. The work required to move a particle with charge q from the other vertex to the center of the line joining the fixed particles is: A. 0 B. kQq/a C. kQq/a2 D. 2kQq/a E. 1.4kQq/a

PHY 2049: Physics II a= 39 cm q1 = 3.4pC q2 = 6 pC E at the center? What is the potential at the center?

PHY 2049: Physics II Capacitors: A device to hold charge. It is held by Coulomb force between the charges. +q and –q on two separate places. V : potential difference: q= CV C: capacitance units farad.

PHY 2049: Physics II

PHY 2049: Physics II