OCR Gateway - P6 - Part 3 0.0 / 5 ? SciencePhysicsGCSEOCR Created by: Connor CreesCreated on: 06-05-16 12:47 What rule do you use to determine the direction of a magnetic field using the direction of current? Right-Hand Thumb Rule 1 of 18 What is a magnetic field? The region where magnetic materials and wires carrying currents experience a force acting on them. 2 of 18 What does adding more turns to the solenoid in an electromagnet do? It increases the strength of the electromagnet. 3 of 18 What rule tells you which way the force acts in a motor? Fleming's Left-Hand Rule 4 of 18 What factors increase the speed of a motor? Increase the current, number of turns and magnetic field strength. 5 of 18 What type of commutator is used in a motor? A split-ring commutator. 6 of 18 What is electromagnetic induction? The creation of a voltage in a wire which is experiencing a change in magnetic field. 7 of 18 In electromagnetic induction, what affects the size of the induced voltage? Strength of the magnet | Area of the coil | Number of turns on the coil | Speed of movement 8 of 18 What is rotated where in a generator to produce a current? A coil is rotated in a magnetic field/ 9 of 18 What do generators used to connect the current? Slip rings and brushes. 10 of 18 How are dynamos different to generators? They rotate the magnet rather that the coil. 11 of 18 What are the three types of transformers? Step-Up | Step-Down | Isolating 12 of 18 What is the core of a transformer made from? Iron 13 of 18 What type of current must be used in a transformer? Alternating Current (AC) 14 of 18 Why must AC be used in a transformer and not DC? DC supplied to the primary coil wouldn't produce a changing magnetic field. 15 of 18 Why must the field in a transformer be constantly changing? So that the current can be induced onto the secondary coil. 16 of 18 What is the formula for finding power? Power = Voltage x Current (P = V x I) 17 of 18 What is the formula for finding power loss? Power Loss = Current^2 x Resistance (P = I^2 x R) 18 of 18
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