Science - Midterm Vocabularies

To light up a bulb, there must be a/an ________ ___________ for electricity to flow from one end of the electric cell to the other.

closed circuit

In a/an __________ ________________, there is a gap, and thus electricity cannot flow.

Open circuit

______________ ______________ allow electricity to flow through them.

Electrical conductors

Metals such as ______________,__ ___________________ and iron are good electrical conductors.

copper, aluminium

The handles of the tools used by an electrician are usually made of _______________, since it is a/an__ _______________ _________________.

plastic, electrical insulator

A ___________ can be used to open or close a circuit.

switch

We can use _______________ to represent circuit components on a diagram

circuit symbols

With circuit symbols and straight lines, we can draw a _____________ ______________ to represent a circuit.

circuit diagram

Matter is made up of ___________.

atoms

In an electric current, each atom has a _______ __surrounded by tiny__ _______________.

nucleus, electrons

In metals, some of the electrons can escape from the atoms and move freely within the metal. These electrons are called ______ ___________________.

free electrons

In a _________________ current, electric currents are a flow of ________ ____ from the positive pole of the electric cell to the negative pole.

conventional, positive charges

We can use an _______ __to measure the size of an electric current. The unit of an electric current is__ __________.

ammeter, ampere

When an electric current flows through nichrome wire, some of the electrical energy charges to thermal energy. This is called the ____________ _____________ of electric current.

heating effect

A current-carrying wire can affect the direction of the needle of a compass. This shows the ________________ ___________ of electric current.

magnetic current

A current-carrying coil acts like a magnet. It is called an _______________.

electromagnet

The _________ of an electric cell is a measure of the amount of energy supplied to the free electrons by the cell.

voltage

We can use a ____________ __to measure voltage. The unit of voltage is__ _______.

voltmeter, volt

The red terminal in a voltmeter is the ______ terminal.

positive

The black terminal in a voltmeter is the _________ terminal.

negative

___________ __measures the opposition of a material to the flow of electric current. It is measured in__ ____.

Resistance, ohm

__________,__ ________,__ __________ are the three factors concerning the resistance of a wire.

material, thickness, length

A ___________ is a circuit component with a fixed value of resistance.

resistor

_____ __rheostats and__ ______________ rheostats are the two types of rheostats commonly used in a school laboratory.

Sliding, rotary-type

A _________ is a circuit component with a resistance that can be adjusted.

Rheostat

Two examples of application of rheostats: the ________ _________ __of a lamp and a hi-fi__ _______________.

dimmer switch, volume control

The circuit which there is only one way to connect two bulbs is called a _______ __circuit.__

series

The circuit in which two light bulbs can be connected in a circuit with branches is called a __________ circuit.

parallel

Nichrome wires are common ________ ___________ in home electrical appliances like electric kettles. When current flows through these wires, electrical energy is converted to thermal energy.

heating elements

The moving parts of electrical appliances are driven by ___________ ___________, which make use of the magnetic effect of electric current to work.

electric motors

Electrical appliances are ________ ___________ that serve many different purposes.

energy converters

Many electrical appliances in our homes get power from the _____ ______________.

main electricity

The main electricity in Hong Kong has a voltage of _______. This voltage is called the__ _______ ___________.

mains voltage

What’s this?

A mains socket

What colour is the live wire?

brown

What colour is the neutral wire?

blue

What colour is the earth wire?

Green and yellow

The pins of a three-pin plug are connected to the _____,__ _____,__ _____ wires

earth, neutral, live

Domestic circuits are _________ circuits so that the electrical appliances can operate independently.

parallel

What’s this?

A consumer unit