The current is the rate of flow of charge. If you take a cross-section of a wire and count how many Coulombs flow the cross-section in one second, the will be the current, expressed in C/s,
or A (Ampere).
In a wire with uniform cross-sectional area A, the current can be shown to be equal to Anqv where n is the number of charge carriers (in conductors, these are electrons), q is the charge
carried by a charge carrier, and v is the drift velocity of the charge carriers.
Ohms law: V = I R. The potential difference across a wire is equal to the resistance R of the wire, times the current in the wire.
For a wire of uniform cross-sectional area A and length L, the resistance is given by R = (rho) L / A, where rho is the resistivity of the material from which the wire is made.
Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.
The book offers a complete review of your AP course, strategies to give you the edge on test day, and plenty of practice with AP-style test questions. It includes full length practice exams modeled on the real test and all the terms and concepts you need to know.
This book includes a review of all the topics tested including vectors, kinematics, fluid mechanics, optics and nuclear physics. Additionally, the book includes two full length tests made complete with descriptive solutions, and quick study tables for Physics B formulas and equations.