F2 IS QZ 08 (8.1-8.3) ans

8.1 - 8.3

Fill in the Blanks (16 marks)

1      A dry cell(1) stores chemical energy and is a source of electrical(1) energy of a circuit.

2      A compete circuit which allows electricity to flow through is called a closed(1) circuit.

An open(1) circuit does not allow electricity to flow through.

3     Materials that allow electricity to pass through are called electrical conductors(1),

while those do not allow electricity to pass through are called electrical insulators(1)

4     Graphite(1) is a non-metal but it allows electricity to pass through.

5     A switch(1) can be used to open or close a circuit.

6     Electric current is the flow of free electrons(1) in a circuit. The direction of

flow is from the negative(1) pole to the positive(1) of the dry cell.

7     An ammeter(1) is an instrument used to measure the size of an electric current.

8     Electric current is measured in amperes(1). Small electric currents are measured in milliamperes (mA).

9     Voltage(1) of a dry cell is the “push” of free electrons to flow through the circuit. It is measured in volts(1) and can be measured by a voltmeter(1).

Circuit Symbol (6 marks)

Draw the circuit of the following electrical components.

Multiple Choice (7 marks)

Circle the letter of the best answer for each question.

1.       Ginny has the following set of electrical components. To build a circuit that can light up a bulb, which of the following components must be used?

(I)   A switch                                  (II)   A dry cell                                (III) Connecting wires

A. (I) and (II) only                B. (I) and (III) only                C. (II) and (III) only      D. All of the above

2.     Which of the following statements about these substances is true?

graphite

plastic

gold

iron

A.   All of them are electrical conductors.                     B.    All of them are electrical insulators.

C.   Only gold and iron are electrical conductors.         D.    Only plastic is an electrical insulator.

3.     Which of the following is a function of a switch?

A.   To break a circuit                                  B.    To supply electrical energy

C.   To control the brightness of a bulb         D.    To protect a bulb from an excessive electric current

4.     Which of the following instruments measures the size of an electric current?

A.   rheostat                   B.    resistor                     C.    voltmeter                 D.    ammeter

5.     The size of an electric current is measured in ___________ .

A.   volts                                B.    amperes                  C.    calories                    D.    joules

Challenging Questions (Bonus 3 marks)

Draw in the following diagram to show how to increase the voltage and current of the circuit. Draw wires to show how the circuit should be connected in order to measure the electric current flowing through the circuit. Indicate the positive (+) and negative (-) terminals of the ammeter.