Electricity and Magnetism
Electricity and Magnetism
Electricity
Circuit symbols
Potential difference
The energy which is delivered to an electric circuit comes from the supply. The greater the potential difference of the power supply the more energy is delivered. Potential difference is measured in volts, which has the unit symbol V.
Cells in series
The more chemical cells that are connected in series the greater the potential difference that they supply. The potential difference of a number of cells connected in series is the sum of each cell separately (bearing in mind the direction in which they are connected.)
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Electric current
The energy supplied by the potential difference is delivered to the circuit by the electric current flowing through the circuit. The current in a metal is actually a flow of electrons (tiny particles that are part of an atom.)
The 1.5V cell supplies enough energy to the current so that it delivers enough energy for the bulb to be normally bright.
Series circuits
All of the current passes through each of the two identical bulbs, the energy supplied by the 1.5V potential difference is shared by the two bulbs, they are each less than normally bright.
Parallel circuits
The current splits at the junction in the circuit. The electrons deliver all of their energy to one or other of the bulbs. Both bulbs obtain the full 1.5V potential difference of the battery, they are each normally bright.
The effects of an electric current
An electric current can cause 1. a heating effect 2. a magnetic effect 3. a chemical effect
Measurement of electric current
Electric current flowing through a component is measured in ampère, A, using an ammeter which is connected in series with the component.
Electric current in a series circuit
The electric current at all points in a series circuit is constant.
Electric current in a parallel circuit
The electric current splits at a junction in a parallel circuit.
Electricity
Circuit symbols
Potential difference
The energy which is delivered to an electric circuit comes from the supply. The greater the potential difference of the power supply the more energy is delivered. Potential difference is measured in volts, which has the unit symbol V.
Cells in series
The more chemical cells that are connected in series the greater the potential difference that they supply. The potential difference of a number of cells connected in series is the sum of each cell separately (bearing in mind the direction in which they are connected.)
.
Electric current
The energy supplied by the potential difference is delivered to the circuit by the electric current flowing through the circuit. The current in a metal is actually a flow of electrons (tiny particles that are part of an atom.)
The 1.5V cell supplies enough energy to the current so that it delivers enough energy for the bulb to be normally bright.
Series circuits
All of the current passes through each of the two identical bulbs, the energy supplied by the 1.5V potential difference is shared by the two bulbs, they are each less than normally bright.
Parallel circuits
The current splits at the junction in the circuit. The electrons deliver all of their energy to one or other of the bulbs. Both bulbs obtain the full 1.5V potential difference of the battery, they are each normally bright.
The effects of an electric current
An electric current can cause 1. a heating effect 2. a magnetic effect 3. a chemical effect
Measurement of electric current
Electric current flowing through a component is measured in ampère, A, using an ammeter which is connected in series with the component.
Electric current in a series circuit
The electric current at all points in a series circuit is constant.
Electric current in a parallel circuit
The electric current splits at a junction in a parallel circuit.