Download Page 1

Q1.
(a) The diagram shows the voltage-current graphs for three different electrical
components.
Which one of the components A, B or C could be a 3 volt filament lamp? Explain the reason for
your choice.
.....................................................................................................................................
............................................................................................................................. ........
.....................................................................................................................................
............................................................................................................................. ........
(3)
(b)
Using the correct symbols draw a circuit diagram to show how a battery, ammeter and voltmeter
can be used to find the resistance of the wire shown.
(3)
(c)
When correctly connected to a 9 volt battery the wire has a current of 0.30 amperes flowing
through it.
(i)
Give the equation that links current, resistance and voltage.
..........................................................................................................................
(1)
(ii)
Calculate the resistance of the wire. Show clearly how you work out your answer and give the
unit.
..........................................................................................................................
..........................................................................................................................
Resistance = .........................................................
(3)
Page 1
(iii) When the wire is heated, the current goes down to 0.26 amperes. State how the
resistance of the wire has changed.
...........................................................................................................................
...........................................................................................................................
(1)
(Total 11 marks)
Q2.
A circuit was set up as shown in the diagram.
(a)
The table gives the current through three of the ammeters. Complete the table to
show the current through the other two ammeters.
Ammeter
Reading on ammeter in
amps
Al
0.2
A2
0.6
A3
0.3
A4
A5
(2)
Page 2
(b)
The reading on the voltmeter is 12 V.
What is the resistance of R2?
Show your working and include the correct unit.
.....................................................................................................................................
............................................................................................................................. ........
.....................................................................................................................................
Resistance = .......................................
(3)
(c)
In the circuit above, the resistor R2 burned out and current stopped flowing in it.
There was no other change to the circuit.
Complete the table below to show the readings on the ammeters after this took
place.
Ammeter
Reading on ammeter in amps
Al
0.2
A2
0.0
A3
A4
A5
(3)
(Total 8 marks)
Page 3
Q3.
The diagram shows a 12 volt lighting system. Each lamp has a power of 32 watts.
(i)
Write down the equation that links current, potential difference and power.
.................................................................................................................. .........
(1)
(ii)
Calculate the input current to the lighting system. Show clearly how you work out
your answer.
............................................................................................................................. .......
.............................................................................................................................. ......
current = ........................................................................ A
(2)
(Total 3 marks)
Page 4
Q4.
The diagram below shows how one type of fuel gauge in a car works. A sliding contact
makes contact with a resistance wire wound in a coil (rheostat). It is connected to a float
via a pivot P. When the petrol level changes the circuit resistance changes. This causes
the pointer in the fuel gauge to move and show how much petrol is in the petrol
tank.
The circuit diagram is shown below.
The petrol gauge is an ammeter. Explain why the reading on the ammeter falls as the
petrol is used.
................................................................................................................................ ...............
................................................................................................................... ............................
............................................................................................................................. ..................
...............................................................................................................................................
(Total 3 marks)
Page 5
M1.
(a)
C
award mark if A and B identified as not filament lamp
1
resistance increases
negated by wrong statement e.g. current goes down
1
as the lamp gets hot
accept as current (through lamp) or voltage (across lamp)
increases
do not accept non-ohmic reason independent of choice of
component
1
(b)
ammeter wire and battery only in series
non standard symbols acceptable if correctly identified
(labelled) for ammeter, voltmeter and battery
1
voltmeter only in parallel with wire or battery
all in series or ammeter in parallel neither of these two
marks awarded
1
all symbols correct
ignore lines drawn through centres of symbols
1
(c)
(i)
voltage = current × resistance
accept V = I × R
accept volts = amps × ohms
do not accept V = C × R
accept
if subsequent method correct
1
(ii)
30
Page 6
accept correct substitution for 1 mark (9/0.3)
2
ohms
accept correct symbol Ω
1
(iii)
goes up
must be a comparison
accept calculation if answer is larger than c (ii)
1
[11]
M2.
(a)
0.9
1
1.1
accept the value of A4 + 0.2
1
(b)
V = I R or 12 = 0.6 R or
accept V = A R
V = I × ohm’s sign
do not credit Ohm’s law triangle
2
R = 20
correct numerical answer earns both marks
ohms
1
(c)
A3 = 0.3
A4 = 0.3
accept the same numeric value as A3
A5 = 0.5
Page 7
accept the value of A4 + 0.2
3
[8]
M3.
(i)
power = potential difference × current
accept voltage for potential difference
accept P = V × I
or correct transposition
accept
provided subsequent method correct
1
(ii)
8
allow 1 mark for correct substitution or transformation or an
answer 2.67 / 2.7
2
[3]
M4.
level drops as petrol used;
causes circuit resistance to increase;
causes current to decrease
for 1 mark each
or if change not specified;
(one correct and two vague statements gains 2 marks,
three vague statements gains 1 mark)
e.g. level changes;
)
so resistance changes; ) = 1 mark
so current changes
)
[3]
Page 8