Lect12 - Physics 212 Physics 212 Lecture 12 Lecture 12...

Info iconThis preview shows pages 1–12. Sign up to view the full content.

View Full Document Right Arrow Icon

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

View Full DocumentRight Arrow Icon

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

View Full DocumentRight Arrow Icon

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

View Full DocumentRight Arrow Icon

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

View Full DocumentRight Arrow Icon

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

View Full DocumentRight Arrow Icon

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

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Physics 212 Physics 212 Lecture 12 Lecture 12 Today's Concept: Today's Concept: Magnetic Force on moving charges Magnetic Force on moving charges = r r r F qv B 5 10 15 20 25 30 35 Avg Avg = 3.2 = 3.2 Confused Confused Confident Confident Today Today s Plan: s Plan: 1) 1) Review of magnetism Review of magnetism 2) 2) Review of cross product Review of cross product 3) 3) Example problem Example problem Key Concepts: Key Concepts: 1) 1) The force on moving charges due to a The force on moving charges due to a magnetic field. magnetic field. 2) 2) The cross product. The cross product. 05 Magnetic Observations N S BarMagnets Compass Needles S N N S N S N S N S N S cut in half 07 N S Magnetic Charge? Compass needle deflected by electric current I Magnetic fields created by electric currents Magnetic fields exert forces on electric currents (charges in motion) V V I I F F V V I I F F Magnetic Observations 12 Magnetism & Moving Charges All observations are explained by two simple equations: = r r r F qv B Today 2 4 = r r I ds r dB r Next Week 14 What do we know about E & B fields? E fields are caused by charges. Those charges can be stationary or moving. B fields are caused by MOVING charges. E field lines start (go out from ) + charges and end in (go into) charges B field lines have no beginning or end No such thing as a magnetic charge has been found (called magnetic monopole). Magnets come with N and S poles together and a N-pole or S-pole cannot be isolated. Notation: X denotes into the page, denotes out of the page. 14 Cross Product Review Cross Product different from Dot Product A B is a scalar; A x B is a vector A B proportional to the component of B parallel to A A x B proportional to the component of B perpendicular to A Definition of A x B Magnitude: ABsin Direction : perpendicular to plane defined by A and B with sense given by right-hand-rule 16 Remembering Directions: The Right Hand Rule F qv B = r r r x y z B F qv 17 Three points are arranged in a uniform magnetic field. The B field points into the screen. 1) A positively charged particle is located at point A and is stationary. The direction of the magnetic force on the particle is: Preflight 2 F qv B = r r r The particle The particle s velocity is zero. s velocity is zero. There can be no magnetic force. There can be no magnetic force. 10 20 30 40 50 60 18 Three points are arranged in a uniform magnetic field. The B field points into the screen. 1) A positively charged particle is located at point A and is stationary. The direction of the magnetic force on the particle is: Preflight 4 F qv B = r r r 10 20 30 40 50 60 A B C D E 21 BB BB X qv B F Cross Product Practice protons (positive charge) coming out of screen Magnetic field pointing down What is direction of force on POSITIVE charge?...
View Full Document

Page1 / 26

Lect12 - Physics 212 Physics 212 Lecture 12 Lecture 12...

This preview shows document pages 1 - 12. Sign up to view the full document.

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