# OCR Gateway - P6 - Part 3

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What rule do you use to determine the direction of a magnetic field using the direction of current?
Right-Hand Thumb Rule
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What is a magnetic field?
The region where magnetic materials and wires carrying currents experience a force acting on them.
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What does adding more turns to the solenoid in an electromagnet do?
It increases the strength of the electromagnet.
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What rule tells you which way the force acts in a motor?
Fleming's Left-Hand Rule
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What factors increase the speed of a motor?
Increase the current, number of turns and magnetic field strength.
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What type of commutator is used in a motor?
A split-ring commutator.
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What is electromagnetic induction?
The creation of a voltage in a wire which is experiencing a change in magnetic field.
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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
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What is rotated where in a generator to produce a current?
A coil is rotated in a magnetic field/
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What do generators used to connect the current?
Slip rings and brushes.
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How are dynamos different to generators?
They rotate the magnet rather that the coil.
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What are the three types of transformers?
Step-Up | Step-Down | Isolating
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What is the core of a transformer made from?
Iron
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What type of current must be used in a transformer?
Alternating Current (AC)
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Why must AC be used in a transformer and not DC?
DC supplied to the primary coil wouldn't produce a changing magnetic field.
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Why must the field in a transformer be constantly changing?
So that the current can be induced onto the secondary coil.
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What is the formula for finding power?
Power = Voltage x Current (P = V x I)
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What is the formula for finding power loss?
Power Loss = Current^2 x Resistance (P = I^2 x R)
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## Other cards in this set

### Card 2

#### Front

What is a magnetic field?

#### Back

The region where magnetic materials and wires carrying currents experience a force acting on them.

### Card 3

#### Front

What does adding more turns to the solenoid in an electromagnet do?

### Card 4

#### Front

What rule tells you which way the force acts in a motor?

### Card 5

#### Front

What factors increase the speed of a motor?