prep 3 U2 lesson 1& 2 T2

Complete the following sentence: When a wire has an electric current in it, .......... are moving along the wire.

• the nuclei of atoms

• electrons

• atoms

Complete the following sentence: The conventional current in a wire is in................ the the flow of electrons in the wire.

• opposite direction to

• same direction as

The picture shows the circuit symbol for a cell.

Which line represents the negative terminal of the cell?

• The longer line

• The shorter line

The diagram shows an electric circuit containing a cell and a bulb. This circuit is set up on a workbench and left on for 1 hour.

At the end of the hour, are there more electrons, fewer electrons, or the same number of electrons in the wires of the circuit than at the start of the hour?

• There are more electrons in the wires.

• There are fewer electrons in the wires.

• There are the same number of electrons in the wires.

Which of the following is the unit of electric current?

• The coulomb

• The joule

• The volt

• The ampere

• The watt

The diagram shows an electric circuit containing a cell and a bulb. This circuit is set up on a workbench and left on for 1 hour.

Over the course of the hour, the bulb gradually becomes dimmer. Which of the following statements correctly explains why?

• The number of electrons in the cell decreases over time, so there are fewer electrons that can flow around the circuit.

• The amount of energy in the cell decreases over time, so there is less energy that can be converted into light by the bulb.

The unit that is used in measuring work is ..............

• ampere

• joule

• coulomb

• ohm

If the work done to transfer an electric charge of 2 coulomb between two points is 100 joule, the potential difference between these two points will be ............... volt.

• 50

• 100

• 200

• 0.5

To transfer electric charge of 10 coulomb between two points the potential difference between them is 20 volts, .................... joules are needed.

• 0.5

• 2

• 20

• 200

The ammeter is used to measure the .............. in the electric circuit.

• potential difference

• e.m.f.

• resistance

• current intensity