* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Slide 1
Electric charge wikipedia , lookup
Casimir effect wikipedia , lookup
Magnetometer wikipedia , lookup
Neutron magnetic moment wikipedia , lookup
Skin effect wikipedia , lookup
Magnetic monopole wikipedia , lookup
Earth's magnetic field wikipedia , lookup
Superconducting magnet wikipedia , lookup
Magnetotactic bacteria wikipedia , lookup
Magnetoreception wikipedia , lookup
Giant magnetoresistance wikipedia , lookup
Magnetotellurics wikipedia , lookup
Electricity wikipedia , lookup
Electromagnetic field wikipedia , lookup
Magnetohydrodynamics wikipedia , lookup
Electromotive force wikipedia , lookup
Force between magnets wikipedia , lookup
Electromagnetism wikipedia , lookup
Faraday paradox wikipedia , lookup
Electromagnet wikipedia , lookup
History of geomagnetism wikipedia , lookup
Magnetochemistry wikipedia , lookup
Aim: How can we explain the 3rd left hand rule of magnetism? Do Now: How will the current flow? To the left rd 3 Left-Hand Rule Used any time you have a charge moving through a magnetic field. When current is placed perpendicular to magnetic field, a force will be produced on the wire. Place thumb in direction of current, and fingers pointing in direction of magnetic field. Your palm will point in the direction the force pushes. Which direction is the force? N Current S Up Describe the motion of the moving charge To figure out the force on a positive charge, use the right hand (or opposite from negative charges) This is how Jay can smash particles together http://www.youtube.com/watch?v=bEvLK 11jdJ8 The resultant of the velocity and the force can produce circular motion Remember… Moving charges create magnetic fields. Your left-hand rules These concepts revolutionized the world Force on a Current Carrying Wire F = IlxB **The x is a cross product – this means the wire and field must be perpendicular to use this formula F = force (N) I = electron flow (A) l = length of wire (m) B = Magnetic Field strength (Tesla = T = N/Am) Example Problem The current flowing in a 2.0 m wire is 100 A. The wire is placed in a magnetic field of 3.0 x 10-3 T such that it is oriented perpendicular to the field. Calculate the force experienced by the wire. F = IlxB F = 100 A(2.0 m)(3.0 x 10-3 T ) F = 0.6 N Force on an Electron An electron entering a magnetic field experiences a force similar to that on a wire (proton would go in the opposite direction). Since F = IlB and I = q/t Then, F = qlB/t, and l/t = v Then the force on any charged particle is F = qvB Mass of an Electron Since a particle is free to move, upon entering a magnetic field, it will constantly change directions in response to the force so,x itx goes x x x xinx a x circle x x x x x x x x x e- x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x p Mass of an Electron Because the electron moves in a circular path the force can also be considered a centripetal force, so F = qvB = mv2/r Therefore, q/m = v/Br 1897: charge to mass ratio (q/m) was determined by J.J. Thomson 1909-1913: charge of an electron was determined by Millikin with his oil drop experiment Mass of electron was then determined with q/m What will happen? S x x x x x N S N Fingers – field The wire will spin Thumb – current This is a motor Palm – force Axis of rotation Electric Motor Converts electrical energy to mechanical energy Motor Demo What will happen? S x x x x x N S N Palm – force Current will be generated Thumb - current This is a generator Fingers – field Axis of rotation Generator Converts mechanical energy to electrical energy Generator Demo AURORAS This is what is happening Known as the northern lights Electrons from violent storms on the Sun enter the Earth’s magnetic field The electrons collide with gases in the Earth’s atmosphere Color depends on the This is what type of atoms and you see molecules struck Proton Aurora Forms from Reconnection Event