PHY 2049: Physics II 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, or you read about it in a brochure/book, 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. Energy conservation applies. F U A uniform electric field, with a magnitude of 600 N/C, is directed parallel to the positive x-axis. If the potential at x = 3.0 m is V, what is the potential at x = 1.0 m? a. 400 Vb Vc Vd V E V

HITT A uniform electric field, with a magnitude of 600 N/C, is directed parallel to the positive x-axis. If the potential at x = 3.0 m is 1000 V, what is the potential at x = 1.0 m? a. 400 Vb Vc V d V

PHY 2049: Physics II What is the potential at the center point (in units of kq/d) ? a) -7(b) -5(c) -7(d) -7

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 C 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 V V r R

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/a 2 D. 2kQq/a E. 1.4kQq/a

PHY 2049: Physics II a= 39 cm q 1 = 3.4pC q 2 = 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

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. Exam I is on Friday May 30, It will be here in class during class time.

PHY 2049: Physics II An outline Capacitors, plate, coaxial, spherical.. Energy, Dielectric strength, Dielectric constant. Netweorks: Parallel and Series configuration.

PHY 2049: Physics II

Potential near a sheet charge

PHY 2049: Physics II

What is the capacitance of various familiar balls. C = 4 πε o R = R(m) F Basketball-it is an insulator Van de Graff top Earth (radius 6.4 X 10 6 m) C E = 0.71 mF

PHY 2049: Physics II Energy stored in a capacitor U = ½ CV 2 = Q 2 /2C = ½ QV Dielectric Strength (oops I burned it/broke it) Capacitor Enhancement by inserting a dielectric: Replace ε o by κε o

PHY 2049: Physics II

Charging and discharging of capacitors. main.uni

PHY 2049: Physics II 25.20

PHY 2049: Physics II Switch closed on left, capacitor C 1 is being charged We have c 2 = c 3 = 20 μF in parallel. The equivalent capacitor is then C eq = 40 μF. When the switch is thrown to right, the battery is disconnected, the charge is shared between the capacitors C 1 and C eq = 40. What is the charge on old C 2 and C 3 ? Is your answer 40 μC? What is your answer if C 2 = 10 μF and C 3 = 30 μF?

PHY 2049: Physics II All about capacitors Capacitance units Farad C = 4 π κε o R Energy stored dielectrics and strength Parallel and series elements in a network

PHY 2049: Physics II