lecture05 - Physics 102 Lecture 05 Circuits and Ohms Law...

Info iconThis preview shows pages 1–7. Sign up to view the full content.

View Full Document Right Arrow Icon
Circuits and Ohm’s Law Physics 102: Lecture 05
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Summary of Last Time Capacitors Physical C = ε 0 A/d C=Q/V Series 1/C eq = 1/C 1 + 1/C 2 Parallel C eq = C 1 + C 2 Energy U = 1/2 QV Resistors Physical R = ρ L/A V=IR Series R eq = R 1 + R 2 Parallel 1/R eq = 1/R 1 + 1/R 2 Power P = IV Summary of Today 5
Background image of page 2
Electric Terminology Current: Moving Charges Symbol: I Unit: Amp Coulomb/second Count number of charges which pass point/sec Direction of current is direction that + flows Power: Energy/Time Symbol: P Unit: Watt Joule/second = Volt Coulomb/sec P = VI 7
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Physical Resistor Resistance: Traveling through a resistor, electrons bump into things which slows them down. R = ρ L /A ρ : Resistivity: Density of bumps L : Length of resistor A : Cross sectional area of resistor Ohms Law I = V/R Cause and effect (sort of like a=F/m) potential difference cause current to flow resistance regulate the amount of flow Double potential difference double current I = (VA)/ ( ρ L) A L 10
Background image of page 4
Preflight 5.1 Two cylindrical resistors are made from the same material. They are of equal length but one has twice the diameter of the other. 1. R 1 > R 2 2. R 1 = R 2 3. R 1 < R 2 2 1 12 77% 3% 21% R = ρ L /A
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Comparison: Capacitors vs. Resistors Capacitors store energy as separated charge: U=QV/2 Capacitance: ability to store separated charge: C =
Background image of page 6
Image of page 7
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 01/25/2012 for the course PHYS 102 taught by Professor Lee during the Spring '08 term at University of Illinois, Urbana Champaign.

Page1 / 21

lecture05 - Physics 102 Lecture 05 Circuits and Ohms Law...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online