Electricity basics

What symbol is this?

Cell

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Battery

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Open Switch

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Closed Switch

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Lamp

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Fuse

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LED

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Power Source

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Resistor

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Variable resistor

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Ammeter

What symbol is this?

Voltmeter

Diode

LDR

Thermistor

motor

What is electrical current?

Electrical current is the flow of electric charge, such as electrons, around a circuit.

What is the unit of current?

The unit of current is the ampere, A.

Define potential difference.

Potential difference (or voltage) is the driving force that pushes the charge around. Its unit is the volt, V.

What role does resistance play in a circuit?

Resistance is something that slows down the flow of current in a circuit. Its unit is the ohm, Ω.

When does current flow through an electrical component?

Current only flows through an electrical component if there's a potential difference across it and if the circuit is closed (complete).

How is potential difference related to resistance and current?

Generally, the higher the potential difference across a component, the higher the current. But the greater the resistance of a component, the smaller the current that flows.

What composes an atom in terms of charge

Atoms contain positive protons and neutral neutrons in the nucleus, with negatively charged electrons orbiting the nucleus.

Describe metals in terms of electron arrangement.

Metals have atoms bonded in such a way that they form a lattice (a grid). These atoms are surrounded by free electrons.

How does current flow in metals?

In metals, the current flows due to the movement of these free electrons.