PHYS 1B Lecture 11: Notes
Document Summary
Electric current: moving charges that produce current can be positive or negative charge or both, by convention, direction flow of current is the direction of flow of positive charges. In most conductors, however, current is actually carried by negative charges (electrons). Drift velocity: current flows when a battery or power supply produces an electric field. Therefore, you get a larger current if: You increase the number of charged particles. You increase the area the charge is in. Ex: suppose a 1mm diameter wire has 1015 electron per mm3 moving at an average drift velocity of 1 microm/s. What is the absolute value of the average current: 1. 26e-7 a, current is always positive. Switching on a light bulb: ele(cid:272)tro(cid:374)s do(cid:374)"t ha(cid:448)e to tra(cid:448)el fro(cid:373) light s(cid:449)it(cid:272)h all the (cid:449)ay to the light (cid:271)ul(cid:271) for the light to operate. If the same potential difference is applied across 2 different conductors, more current will flow in the one that has lower resistance.
