1 John Parkinson © 2 THE AURORA The Aurora Borealis, the Northern Lights and the Aurora Australis, the Southern lights are phenomena resulting from the

Embed Size (px)

Text of 1 John Parkinson © 2 THE AURORA The Aurora Borealis, the Northern Lights and the Aurora Australis,...

  • John Parkinson

    JP

  • THE AURORAThe Aurora Borealis, the Northern Lights and the Aurora Australis, the Southern lights are phenomena resulting from the interaction between Solar Wind and the Earths magnetic field.

    JP

  • NSLines of magnetic flux, Magnetic flux density, B, measures the strength of the magnetic field.B = number of lines of flux per square metreUNITS are Webers per square metre Wb m-2 or TESLAS (T)B IS A VECTOR QUANTITY

    JP

  • NSLines of magnetic flux, ATotal magnetic flux through area A is given by: = B A webers, when the area is perpendicular to the field = B A sin

    JP

  • JP

  • 1820Professor Oersted was demonstrating an experiment for students when he accidentally discovered that a compass needle moved when it was close to a wire connected to a battery.Professor Hans Christian Oersted

    JP

  • B

    JP

  • B

    JP

  • RIGHT HAND GRIP RULE:

    JP

  • current outwardscurrent inwardsB

    JP

  • IN turnsIn the middleat the end

    JP

  • NSInteraction between a magnet and the field due to a current

    JP

  • JP

  • FLEMINGS LEFT HAND MOTOR RULE

    JP

  • FLEMINGS LEFT HAND MOTOR RULEFOREFINGER = FIELDTHUMB = MOTIONSECOND FINGER = CURRENT

    JP

  • F = B I lWhere l = length of conductor in the field

    JP

  • MOVING COIL METER

    JP

  • JP

  • NSEVERY TIME THE COIL PASSES THROUGH THE VERTICAL POSITION, THE COMMUTATOR REVERSES THE CURENT IN THE COIL, IN ORDER TO SUSTAIN THE ROTATIONDC MOTOR

    JP

  • LOUDSPEAKERAC signal

    JP

  • JP

  • Force experienced by a charged particle (charge Q) moving with a velocity, v in a magnetic field of Flux density, B+QParticle travels l metres from A to B in t secondsF = B I lF = B Q v

    JP

  • +FFTHE FORCE IS ALWAYS PERPENDICULAR TO THE MOTIONTHE PARTICLE MUST MOVE ALONG AN ARC OF A CIRCLE+

    JP

  • Frequency of Rotation, f+The frequency is independent of the radius and the velocityThis is the principle of the CYCLOTRON

    JP

  • CYCLOTRON+High frequency square wave

    JP