Contents
Key Stage 1
Meaning
This bulb has a filament inside it that glows when electricity goes through it.
A light bulb is something that lights up when you switch it on.
Key Stage 2
Meaning
An electrical bulb is a circuit component that gives out light when electricity goes through it.
About Electrical Bulbs
- There are many different kinds of electrical bulb.
- The type of electrical bulb you will use in class is called a Filament Bulb. It has a thin piece of wire inside that glows when electricity passes through it.
- Electrical bulbs can get very hot so you shouldn't touch the glass.
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| An electrical bulb. | The symbol for an electrical bulb. |
Key Stage 3
Meaning
An electrical bulb is a circuit component that gives out light when electricity goes through it.
About Electrical Bulbs
- There are many different kinds of electrical bulb.
- The type of electrical bulb used in class is called a Filament Bulb. It has a thin piece of wire called a filament that becomes so hot when electricity passes through it that it begins to glow.
- Electrical bulbs can get very hot so you shouldn't touch the glass.
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| An electrical bulb. | The symbol for an electrical bulb. |
Key Stage 4
Meaning
An electrical bulb is a circuit component that gives out light when electricity goes through it.
About Electrical Bulbs
- An electrical bulb usually refers to a Filament Bulb. However, there are other types.
- In a filament bulb electrical work is done to heat the filament to a high enough temperature that it glows in visible light, see black body radiation.
- The electrical current has a heating effect on the filament which increases its temperature. This causes the resistance to increase, so the bulb does not behave as an ohmic conductor.
IV Graph
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Description
The IV Graph for a bulb shows that:
- As potential difference increases, increases.
- At small potential differences] the the relationship between potential difference and current is linear (the gradient is constant).
- At large potential differences the gradient becomes more shallow as the resistance of the bulb increases.
Explanation
- At small potential differences there is a small current so the heating effect of the current is small and the filament remains at a low temperature.
- At large potential differences there is a large electrical current so the heating effect of the current is large which causes the filament to be a high temperature.
- Wires (like the filament) have a greater resistance at higher temperatures, causing the increase in current to be reduced.