In the UK, What Type of Current is the Current from the Plug Socket?
Alternating Current
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Whats a DC and AC?
Direct Current, when a current only flows in one direction. Alternating current, When the current flows in both directions
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What Feature of the Wire Tells You its Purpose
Its Colour
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What Are the Different Wires in a Plug Socket and what Colours are they?
Earth Wire - Green and Yellow. Neutral Wire - Brown. Live Wire - Blue.
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Which Type of Wire is Used to Prevent Shock
Earth Wire
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How many types of wire are found in cables connecting to the mains?
3
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What are 2 equations to calculate power?
power = potential difference x current. power = current^2 x resistance.
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Name the two equations use to calculate Energy Transferred.
energy transferred = power x time. energy transferred = charge x potential difference.
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How much energy does a 50W bulb use per second?
50J because energy transferred = power x time. (50 watts x 1 second = 50J)
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How much energy is used by an appliance with a power rating of 10W connected to the mains for 5s?
1. Remember the equation for energy used E = P × t. 2. Substitute the values in. E = 10 × 5. 3. Answer E = 50J
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Whats the National Grid?
The National Grid is the network of cables and transformers that connect power stations with houses and shops in the United Kingdom.
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What is the potential difference across the mains power supply in the UK?
230V
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Name three properties of a circuit breaker
Switches off current, reusable and measures current
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What is a Fuse?
A fuse is a thing that contains a thin wire that melts if the current flowing through an appliance is too high. This breaks the circuit and stops the flow of electric current.
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What is a Circuit Breaker?
Circuit breakers are special devices that switch off the flow of current if the current is higher than a certain value. Circuit breakers do the same job as fuses but can be used lots of times.
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Whats one difference between Fuses and Circuit Breakers?
Circuit breakers are reusable
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Whats a Fuse Rating?
Fuse ratings tell us the level where a fuse will begin to melt. The fuse chosen should have a value just above the normal current that an electrical appliance uses.
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Which fuse should you use for an appliance with an operating current of 6.5A?
7A
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What do you need to know to select an appropriate fuse for a kettle?
The potential difference of the power supply, power label found on EU devices and the Equation for power:
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How does an Earth Wire prevent shock?
the resistance of the Earth wire is low, a very high current will flow through it, breaking the fuse in the device. This will stop the flow of current and make the appliance safe.
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What would happen if you touched a live wire?
If you touched the live wire, your body would supply a link between the supply and the ground. This is an electric shock.
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Earth wires are needed for appliances with what?
Metal Casing
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Why can a live wire still be dangerous when the power is switched off?
It might still hold some potential difference.
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Other cards in this set
Card 2
Front
Whats a DC and AC?
Back
Direct Current, when a current only flows in one direction. Alternating current, When the current flows in both directions
Card 3
Front
What Feature of the Wire Tells You its Purpose
Back
Card 4
Front
What Are the Different Wires in a Plug Socket and what Colours are they?
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