Magnetism and Electromagnetism

• Wha t is induced magnet 


  -materials that become magnetic when in magnetic fields

  -they always have a force of attraction

  -these align the domains in the material all in the same direction,creating temporary magnet
• What is the motor effect?

  -2 magnets interact feeling a magnetic force of attraction/repulsion

  -so a magnet and a wire will also exert s force as the 2 magnetic fields will also interact

  -magnetic field around the wire is a circular but the magnetic field between 2 magnets are straight

  -when 2 interact the wire is pushed away from the field between the poles (at right angles to the wire direction
• What are the 2 factors that affect the strength of the magnetic field

  -greater current

  -shorter distance from the wire
• explain the earth's core?

  • the core is magnetic and creates a large magnetic fields around the earth

  -because a freely suspended magnetic compass will allign itself with the earth's field lines and point north
• What is an solenoid?

  -magnetic field shape is simillar tobar magnet

  -it enchances themagnetic effect as coiling the wire causes the field to allign and form a giant single,field rather than lots of them all perpendicular to the direction of the current
• what factors affect the strength of the solenoid

  -size of current,length,cross sectional area,

  -number of turns

  -using a soft iron core
• how do electric motors work?

  -in between,a coil of current-carrying wire lies on the x-axis

  -force on one side moves that side up

  -force on other side(where current flowsing in opposite direction) moves down

  -this can be vertified using fleming rule

  -hence it rotates
• What is Fleming's left hand rule?

  -each direction is 90degrees to each other

  -use this to workout the unknown factor out of the three

  -the current is conventional current,which moves in opposite direction to the electrons
• Investigating springs


  1Attach spring to the clamp stand by hanging it off a clamo and let eh spring hang freely over the side of the bench.

  -Use the other clamps to hold the ruler vertically.use this to measure the spring

  -Measure the length of the spring

  -Hang the mass holder from the spring.Record the length

  -Add 0.5 N/50gweight and measure the length

  -Repeat until 250g and record length of spring and total mass
• Investigating acceleration


  1. Position an air track on a bench with a bench pulley at one end and two light gates above the track

  2. Cut an interrupt card to a known length (such as 10 cm) and attach it to an air track glider

  3. Connect the glider to a hanging mass by a string the length of the air track passing over the bench pulley

  4. Make sure the air track is level and that the card will pass through both gates before the mass strikes the floor

  5. Set the data logging software to calculate acceleration
• Experiment steps


  1. Add 5 × 20 g slotted masses (0.98 N of force) to the end of the string

  2. Release the glider, then record the weight and acceleration

  3. Repeat steps 4 and 5 two more times, and calculate a mean value for the acceleration

  4. Repeat steps 4 to 6, removing one of the slotted masses each time (giving forces of 0.78 N, 0.59 N, 0.39 N and 0.20 N)