Feb7note1

Feb7note1 - PHYS142 Lecture 14 Current and Resistance...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
Current and Resistance • Chapter 27 All sections except 3 27.1 Electric Current 27.2 Resistance 27.3 A Model for Electrical Conduction 27.4 Resistance and Temperature 27.5 Superconductors 27.6 Electrical Power 1 PHYS142 Lecture 14
Background image of page 1

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

View Full DocumentRight Arrow Icon
What does R depend on? Geometry of the conductor Material of the conductor Scattering of the free electrons through collisions is the main source of resistance. Collisions increase the vibration of atoms. + e e e e e e 2
Background image of page 2
A L ρ R Where ρ is the resistivity of the material (independent of geometry). Units for ρ : m ( cm) Conductivity ρ σ 1 3 Resistance and Resistivity Combining two relations, R G 1 Conductance
Background image of page 3

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

View Full DocumentRight Arrow Icon
Resistance and temperature (27.4) When the temperature increases , there is more thermal energy available to the atoms. The atoms vibrate with a larger amplitude and provide a much larger scattering target for the free electrons. 4
Background image of page 4
Image of page 5
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 02/22/2011 for the course PHYS 142 taught by Professor Altounian during the Spring '07 term at McGill.

Page1 / 10

Feb7note1 - PHYS142 Lecture 14 Current and Resistance...

This preview shows document pages 1 - 5. Sign up to view the full document.

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