chapter 13 : electrical systems Flashcards
What are the main components of an electrical system?
- cell (battery)
- electric charge
- connecting wires
- electrical devices eg bulb
what is the rate at which electric charge flows?
electric current, I
the greater the flow of electric charge per unit time,
the larger the current
what is an ammeter for?
to measure the current flowing through an electric circuit
how is an ammeter arranged to measure the current flowing?
the ammeter is connected in series within a circuit
what is the SI unit of electric current?
ampere (A)
the negative terminal of the ammeter is connected to?
the negative side of the cell
what is the use of a voltmeter?
to measure the potential difference between two points in an electric circuit
what is the SI unit for potential difference?
volt (V)
how is a voltmeter arranged to measure the potential difference across an electrical component?
a voltmeter is connected in parallel to the electrical component
what is electrical resistance, R?
a measure of how much the component opposes the flow of electric current
the negative terminal of the voltmeter is connected to?
the negative end of the cell
electrical conductors have very low resistance to current,
electrical insulators have very high resistance to current, too high until current cannot flow through them.
what are resistors?
electrical components that reduce the flow of current in a circuit.
what is the SI unit of electrical resistance?
ohm
what happens when a resistor is added to a circuit?
it will be more difficult for electric charge to flow in the circuit
what are the two types of resistors?
- fixed resistor, which has fixed, non-adjustable electrical resistance
- variable resistor, which has a range of electrical resistance that can be adjusted
variable resistors are used in households?
to control the current in a circuit. eg dimmers
what is a rheostat?
a type of variable resistor that can be adjusted to control the amount of current flowing through a circuit.
what is the SI unit of power
watt (W)
what is fuse?
an electrical component that is used to protect the electrical appliance from excess current
when multiple plugs are inserted into the same socket,
a very large amount of current may be drawn from the power supply, which can result in excessive heat, causing wires to melt and even cause a fire
how to increase electromagnetism?
- more no. of coils
- more no. of cells
