# P5

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What do step up transformers do?
They increase voltage
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What do step down transformers do?
They decrease voltage
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How many cells are there in a battery?
2
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What is electromagnetic induction?
Electromagnetic induction is when voltage is induced from a changing magnetic field. The magnetic field changes because of the coil of wire wrapped around the magnet,which is in the iron core.
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What is AC and DC?
AC is alternating current (always changing direction) and DC is direct current (always flows in one direction)
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How does alternating current make transformers change the size of voltage?
As AC is always changing, it forces the magnet to continuously flip. This changes the magnet field , which creates an electromagnetic induction therefore inducing a voltage, which can be changed through the use of step up and step down transformers.
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Why will AC work in a transformer but not DC?
DC always flows in one direction so it cannot change the magnet field and cannot induce a voltage.
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What is the difference (in appearance / features) between a step up and step down transformer?
A step up transformer has more turns on the secondary coil whereas the step down transformer has more turns on the primary coil
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What is the differnce between parallel and series circuits when it comes to current?
In series current is the same in all components as they are all on one branch of the circuit but parallel shares the current because there are different branches with components not all joined together.
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What are LDR's and Thermistors examples of and what do they stand for?
They are resistors. A LDR is a light dependant resistor and a thermistor is a temperature dependent resistor
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What is the differnce between parallel and series circuits when it comes to potential difference?
The total potential difference in series has been shared whereas in a parallel it is the same across all components.
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What is potential difference?
Potential difference is a measurement of the amount of energy transferred between two points in a circuit.
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What device measures voltage and what is it measured in?
Voltmeter, volts (V)
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What device measures current and what is it measured in?
Ammeter, amps (A)
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What is resistance measured in?
Ohms
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What are the four main things that affect the size of voltage when it is induced?
1. An iron core. 2. Increasing the strength of the magnetic field. 3. Increasing the speed of rotation. 4. Increasing the number of turns on the coil.
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How do you find out resistance if you know what the voltage and current is?
Voltage divide by current.
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How do you find out current if you know what the voltage and resistance is?
Voltage divide by resistance
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How do you find out voltage if you know what the current and resistance is?
Current times by resistance
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Why do resistors get hot when current passes through them?
When electrons (negative charge) move through a resistor, they collide with positive ions in the resistor. These collisions cause the ions to vibrate more, which causes an increase in temperature
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## Other cards in this set

### Card 2

#### Front

They decrease voltage

#### Back

What do step down transformers do?

### Card 3

2

#### Back ### Card 4

#### Front

Electromagnetic induction is when voltage is induced from a changing magnetic field. The magnetic field changes because of the coil of wire wrapped around the magnet,which is in the iron core.

#### Back ### Card 5

#### Front

AC is alternating current (always changing direction) and DC is direct current (always flows in one direction)

#### Back 