P15 - Electromagnetism 3.0 / 5 based on 2 ratings ? PhysicsElectromagnetismGCSEAQA Created by: abrundell14Created on: 31-01-19 19:09 Magnetic field lines curve from: North pole to south pole 1 of 32 What is used to make permanent magnets? Steel 2 of 32 Why is this metal used for magnets? Does not loose magnetism easily 3 of 32 What is a solenoid? A long coil of insulated wire 4 of 32 What is an electromagnet? An insulated wire wrapped around around an iron bar 5 of 32 What is the equation for force? F=BIL 6 of 32 What does B stand for? Magnetic flux density 7 of 32 What does I stand for? Current 8 of 32 What does L stand for? Length of conductor 9 of 32 First finger of Flemming's left hand rule? Field 10 of 32 Thumb of Flemming's left hand rule? Movement 11 of 32 Second finger of Flemming's left hand rule? Current 12 of 32 Magnetic flux density is measured in? Teslas, T 13 of 32 Pd can be increased by: Moving the wire/ magnet faster 14 of 32 Pd can be increased by: Increasing strength of the magnetic field 15 of 32 Pd can be increased by: Using a coil with more turns 16 of 32 A Pd is induced when: An electrical conductor cuts through magnetic field lines 17 of 32 What is the difference between an a.c generator and a d.c generator? A d.c generator has a split-ring commutator instead of two slip rings 18 of 32 An a.c. generator's induced pd is at its peak when: The sides of the coil cross directly through the magnetic field lines 19 of 32 An a.c. generator's induced pd is at its zero-value when: The sides of the coil are parallel to the field lines 20 of 32 The faster an a.c. coil rotates: The higher the frequency, the greater the peak value 21 of 32 What is an a.c. generator/ alternator? A rectangular coil that spins in a magnetic field, producing a pd that is alternately positive and negative 22 of 32 What is a d.c. generator/ dynamo? A coil spinning in a magnetic field that produces a positive pd 23 of 32 What is a transformer used for? Increasing/ decreasing the size of an alternating pd 24 of 32 What is a transformer made up of? A primary coil, a secondary coil and an iron core 25 of 32 Why does a transformer only work with a.c.? A changing magnetic field is necessary to induce a.c. in the secondary coil 26 of 32 A step-up transformer has: More turns on the secondary coil 27 of 32 A step-down transformer has: More turns on the primary coil 28 of 32 What is the core of a transformer made of? Iron, so it can be easily magnetised/ demagnetised 29 of 32 The transformer equation is (V is pd): Vp/Vs=Np/Ns 30 of 32 For a 100% efficient transformer (I is current): Vp*Ip=Vs*Is 31 of 32 A high grid pd: Reduces the current, reducing power loss 32 of 32
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