Physics 3- Electromagnetism 5.0 / 5 based on 1 rating ? PhysicsElectromagnetismGCSEWJEC Created by: purplehydroplumCreated on: 23-05-16 09:43 Define a magnetic field Where magnetic materials feel a force 1 of 37 How are magnets fields made? By magnets or a current through a wire 2 of 37 Describe the magnetic field of a bar magnet Circular lines going from North to South, lines closer at each end. 3 of 37 What can be concluded about the area of a magnetic field where the field lines are closer? That is where the field is strongest 4 of 37 Describe the magnetic field of a straight wire with a current going through it Lines around wire in a anticlockwise direction, getting further apart further from the wire 5 of 37 What can be deduced from the fact field lines around a wire with a current through it get further apart the further from the wire they are? The field becomes weaker further from the wire 6 of 37 What is the direction of the circular field lines around a flat coil? Clockwise (relating to direction of coil) 7 of 37 Define a solenoid Long coil with a field running through it 8 of 37 Describe the magnetic field of a solenoid Circular lines from one end of the coil to the other (right to left) with straight lines down the middle 9 of 37 What do the parallel lines through a solenoid show about the magnetic field? It has constant strength through the middle of the solenoid 10 of 37 Define the Motor Effect Where the magnetic effect of electricity produces movement 11 of 37 Describe the magnetic field/s produced by a current-carrying wire in the magnetic field of two permanent? 2 magnetic fields on top of eachother, 1 from the permanent magnets, 1 from the electricity flowing through the wire. 12 of 37 What do these two fields produce? A force which prompts movement 13 of 37 How is the size of this force increased? By increasing the current, magnetic field strength or number of wires in the field 14 of 37 What kind of movement can the motor effect produce on the wire? Rotational effect 15 of 37 How can the direction of the force be predicted in the Motor Effect? Flemming's LEFT hand rule 16 of 37 In Flemming's Left hand rule, what does the thumb represent? The direction of motion 17 of 37 What, in the Flemming's left hand rule, is the direction of field represented by? The first finger 18 of 37 What does the second finger represent? The current 19 of 37 Describe the force produced when a current is put through a coil and what does it prompt? Upwards force on one side, downwards force on the other, the coil turns 20 of 37 What does a split ring communicator in a motor do? Ensure the force acts upwards on one side, downwards on the other, continuously in one direction. 21 of 37 Define Induction When a metal wire cuts through a magnetic field 22 of 37 What does a wire cutting through a magnetic field produce? A voltage across the wire 23 of 37 what happens if the aforementioned wire is connected to a circuit? The voltage pushes a current around the circuit, ELECTRICITY IS INDUCED 24 of 37 Does it matter, in the case of induction, whether it's a magnet inside a coil or a coil inside a magnetic field? No 25 of 37 What is the relationship between the output voltage or current and the speed of rotation or number of turns on a generator? They are proportional 26 of 37 What happens to this when the magnetic field strength increases? It increases 27 of 37 How might one find the direction of the induced current? Flemming's Right Hand Rule 28 of 37 What does the circular motion in generators usually produce? An alternating current/voltage 29 of 37 What does 'an alternating current/voltage' mean? They change regularly 30 of 37 What do most of the circular motions in generators mean? Output current is constantly changing in size? 31 of 37 How to transformers induce electricity? By using a changing magnetic field 32 of 37 What does a step up/step down transformer do? Increase/decrease voltage 33 of 37 Wjhat is the iron core used for in a transformer? Used as a magnetic material to transfer the magnetic field between coils 34 of 37 What does the alternating current of the primary coil show about the magnetic field around it? It's changing 35 of 37 What induces a voltage in the secondary coil? Constantly changing field 36 of 37 What does the voltage size depend on? The number of turns on the coil 37 of 37
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