Physics 2102 Lecture 14 Ch28: Magnetic Forces on Current Wires Physics 2102 Jonathan Dowling Star Quake on a Magnetar! “I’ll be back…. Aurora Borealis.

Slides:



Advertisements
Similar presentations
Torque On A Current Loop In A Uniform Magnetic Field
Advertisements

Magnetic Fields Due To Currents
Phy 213: General Physics III Chapter 28: Magnetic Fields Lecture Notes.
Physics 2102 Lecture 15 Biot-Savart Law Physics 2102 Jonathan Dowling Jean-Baptiste Biot ( ) Felix Savart (1791–1841)
Phys 102 – Lecture 12 Currents & magnetic fields 1.
Currents and Magnetism Textbook Sections 22-4 – 22-7 Physics 1161: Lecture 11.
Lecture 27: FRI 20 MAR Magnetic Fields III Physics 2113 Jonathan Dowling “They are not supposed to exist….” Aurora Borealis.
Physics 2102 Magnetic fields Physics 2102 Gabriela González.
Wednesday, Oct. 26, 2005PHYS , Fall 2005 Dr. Jaehoon Yu 1 PHYS 1444 – Section 003 Lecture #16 Wednesday, Oct. 26, 2005 Dr. Jaehoon Yu Charged Particle.
Physics 2102 Gabriela González Physics 2102 Magnetic fields L.
Physics 1502: Lecture 15 Today’s Agenda Announcements: –Answers to midterm 1 NO Homework due this weekNO Homework due this week Magnetism.
AP Physics C Magnetic Fields and Forces. Currents Set up Magnetic Fields First Right-Hand Rule Hans Christian Oersted ( )
Currents and Magnetism Textbook Sections 22-4 – 22-7 Physics 1161: PreLecture 13.
Certain objects and circuits produce magnetic fields Magnetic fields, like electric fields, are vector fields They have a magnitude and a direction Denoted.
Physics 2102 Lecture 15 Magnetic fields Physics 2102 Jonathan Dowling
1 Chapter 29: Magnetic Fields due to Currents Introduction What are we going to talk about in chapter 30: How do we calculate magnetic fields for any distribution.
Wed. Feb. 18 – Physics Lecture #30 Magnetic Fields 1. Magnetic Fields 2. Magnetic Moments & Torque 3. Ampere’s Law Warm-Up, Discuss with Neighbors: Wire.
Physics Magnetism 20.1 Magnets and magnetic fields 20.2 Electric currents produce magnetism 20.3 Force on current in magnetic field 20.4 Force.
Physics Magnetic Fields 29.1 Magnetic Fields (B) and Forces (F) 29.2 Motion of a Charged Particle in B 29.3 Applications: Charged Particle in.
Chapter 21 Magnetic Forces and Magnetic Fields Magnetic Fields The needle of a compass is permanent magnet that has a north magnetic pole (N) at.
1 19 Overview magnetic force fields & sources forces on charges & currents Homework: 3, 7, 10, 33, 45, 55, 75.
Magnetic Fields due to Currentss
Physics 2102 Magnetic fields produced by currents Physics 2102 Gabriela González.
Magnetic Forces and Torques
Magnetism Forces caused by Magnetic Fields. Magnetic Fields Measured in Teslas (T) or Gauss (G) 10,000 G = 1 T Moving charge causes magnetic fields Remember.
Thursday, Nov. 3, 2011PHYS , Fall 2011 Dr. Jaehoon Yu 1 PHYS 1444 – Section 003 Lecture #18 Thursday, Nov. 3, 2011 Dr. Jaehoon Yu Torque on a Current.
Physics 121 Practice Problem Solutions 09 Magnetic Fields
1 Chapter 19: Magnetism The nature of magnetism Iron ore found near Magnesia Compass needles align N-S: magnetic Poles North (South) Poles attracted to.
5. Magnetic forces on current l A Example: A straight wire carrying a current is placed in a region containing a magnetic field. The current flows in the.
Currents and Magnetism
Lecture 25: MON 16 MAR Magnetic fields Ch.28.1–4 Physics 2113 Jonathan Dowling “I’ll be back…. Aurora Borealis.
Tuesday March 29, PHYS Dr. Andrew Brandt PHYS 1444 – Section 02 Lecture #15 Tuesday Mar Dr. Andrew Brandt HW7 Ch 27 is due Fri.
PHYS 1442 – Section 004 Lecture #12 Wednesday February 26, 2014 Dr. Andrew Brandt Chapter 20 -Charged Particle Moving in Magnetic Field -Sources of Magnetic.
Phys 102 – Lecture 11 Magnetic dipoles & current loops.
Lecture 27 Magnetic Fields: II
5. Magnetic forces on current
Torque on a Current Loop
Lecture 32: MON 09 NOV Review Session A : Midterm 3 Physics 2113 Jonathan Dowling.
Lecture 25: FRI 24 OCT Magnetic Fields III
Physics 212 Lecture 14, Slide 1 Physics 212 Lecture 14 Biot-Savart Law :05.
Lecture 21: FRI 06 MAR Magnetic fields Ch Physics 2102 Jonathan Dowling 28.8 Force on Current in Wire 28.9 Torque on Current Loop Magnetic.
Certain objects and circuits produce magnetic fields Magnetic fields, like electric fields, are vector fields They have a magnitude and a direction Denoted.
Physics 102: Lecture 9, Slide 1 Currents and Magnetism Today’s lecture will cover Textbook Sections Physics 102: Lecture 09.
Principles of Electromechanics Electricity  Motion Electricity  Motion: Motor Motion  Electricity: Generator  Magnetic Field & Faraday’s Law.
PHYS 1444 – Section 501 Lecture #15
Torque On A Current Loop In A Uniform Magnetic Field
Magnetic Forces and Fields
Magnetic Forces and Torques
Figure 22-1 The Force Between Two Bar Magnets
Magnetic Fields Ch. 29 Certain objects and circuits produce magnetic fields Magnetic fields, like electric fields, are vector fields They have a magnitude.
The Torque on a Current-Carrying Coil
5. Magnetic forces on current
Magnetic Fields Ch. 29 Certain objects and circuits produce magnetic fields Magnetic fields, like electric fields, are vector fields They have a magnitude.
Exam 2: Tuesday, March 21, 5:00-6:00 PM
Magnetism Physics /10/2018 Lecture XII.
Lecture 14: TUE 09 MAR Magnetic Fields II Ch Physics 2102
Lecture 25: WED 21 OCT Magnetic Fields III
Review and some interesting consequences of F=qvxB.
Lorentz Forces The force F on a charge q moving with velocity v through a region of space with electric field E and magnetic field B is given by: 11/23/2018.
Magnetic Fields Contents: Overview What Produces Magnetic Field
Currents and Magnetism
A reminder about current
Lecture 19: MON 02 MAR Magnetic fields Ch Physics 2102
Active Figure 29.1 Compass needles can be used to trace the magnetic field lines in the region outside a bar magnet.
8.1 – Magnets and Electromagnets (pg )
5. Magnetic forces on current
Magnetic Fields Ch. 28 Certain objects and circuits produce magnetic fields Magnetic fields, like electric fields, are vector fields They have a magnitude.
Currents and Magnetism
Magnetic Fields due to Currentss
Magnetic Fields Ch. 28 Certain objects and circuits produce magnetic fields Magnetic fields, like electric fields, are vector fields They have a magnitude.
Presentation transcript:

Physics 2102 Lecture 14 Ch28: Magnetic Forces on Current Wires Physics 2102 Jonathan Dowling Star Quake on a Magnetar! “I’ll be back…. Aurora Borealis

Crossed Fields E vs. B F E =qE B E y q F B =vqBF E v L F E =ma => y=qEL 2 /(2mv 2 ) F B =F E => y=0 => v=E/B

Magnetic force on a wire. L Note: If wire is not straight, compute force on differential elements and integrate:

Example By symmetry, F 2 will only have a vertical component, Notice that the force is the same as that for a straight wire, LLRR and this would be true no matter what the shape of the central segment!. Wire with current i. Magnetic field out of page. What is net force on wire?

Example 4: The Rail Gun Conducting projectile of length 2cm, mass 10g carries constant current 100A between two rails. Magnetic field B = 100T points outward. Assuming the projectile starts from rest at t = 0, what is its speed after a time t = 1s? B I L Force on projectile: F= ILB (from F = iL x B) Acceleration: a = iLB/m (from F = ma) v(t) = iLBt/m (from v = v 0 + at) = (100A)(0.02m)(100T)(1s)/(0.01kg) = 2000m/s = 4,473mph = MACH 8! projectile rails

Torque on a Current Loop: Principle behind electric motors. Net force on current loop = 0 For a coil with N turns,  = N I A B sin , where A is the area of coil Rectangular coil: A=ab, current = i But: Net torque is NOT zero!

Magnetic Dipole Moment N = number of turns in coil A=area of coil. We just showed:  = NiABsin  Right hand rule: curl fingers in direction of current; thumb points along  Define: magnetic dipole moment  As in the case of electric dipoles, magnetic dipoles tend to align with the magnetic field.

Electric vs. Magnetic Dipoles -Q  QE +Q p=Qa