1
(a)
Figure 1 shows the oscilloscope trace an alternating current (a.c.) electricity supply
produces.
Figure 1
One vertical division on the oscilloscope screen represents 5 volts.
Calculate the peak potential difference of the electricity supply.
.............................................................................................................................
Peak potential difference = ................................................. V
(1)
(b)
Use the correct answer from the box to complete the sentence.
40
50
60
In the UK, the frequency of the a.c. mains electricity supply is ............ hertz.
(1)
(c)
Figure 2 shows how two lamps may be connected in series or in parallel to the 230 volt
mains electricity supply.
Figure 2
Page 1 of 26
(i)
Calculate the potential difference across each lamp when the lamps are connected in
series.
The lamps are identical.
...................................................................................................................
Potential difference when in series = ..................... V
(1)
(ii)
What is the potential difference across each lamp when the lamps are connected in
parallel?
Tick (✔) one box.
115 V
230 V
460 V
(1)
(iii)
Give one advantage of connecting the lamps in parallel instead of in series.
...................................................................................................................
...................................................................................................................
(1)
(d)
Figure 3 shows the light fitting used to connect a filament light bulb to the mains electricity
supply.
Figure 3
The light fitting does not have an earth wire connected.
Explain why the light fitting is safe to use.
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
(2)
Page 2 of 26
(e)
A fuse can be used to protect an electrical circuit.
Name a different device that can also be used to protect an electrical circuit.
.............................................................................................................................
(1)
(Total 8 marks)
2
(a)
The diagram shows the circuit that a student used to investigate how the current through a
resistor depends on the potential difference across the resistor.
(i)
Each cell provides a potential difference of 1.5 volts.
What is the total potential difference provided by the four cells in the circuit?
...............................................................................................................
Total potential difference = .................................................. volts
(1)
(ii)
The student uses the component labelled X to change the potential difference across
the resistor.
What is component X?
Draw a ring around your answer.
light-dependent resistor
thermistor
variable resistor
(1)
(iii)
Name a component connected in parallel with the resistor.
...............................................................................................................
(1)
Page 3 of 26
(b)
The results obtained by the student have been plotted on a graph.
(i)
One of the results is anomalous.
Draw a ring around the anomalous result.
(1)
(ii)
Which one of the following is the most likely cause of the anomalous result?
Put a tick (
) in the box next to your answer.
The student misread the ammeter.
The resistance of the resistor changed.
The voltmeter had a zero error.
(1)
(iii)
What was the interval between the potential difference values obtained by the
student?
...............................................................................................................
...............................................................................................................
(1)
Page 4 of 26
(c)
Describe the relationship between the potential difference across the resistor and the
current through the resistor.
........................................................................................................................
........................................................................................................................
(1)
(Total 7 marks)
3
A student set up the electrical circuit shown in the figure below.
(a)
The ammeter displays a reading of 0.10 A.
Calculate the potential difference across the 45 Ω resistor.
.............................................................................................................................
.............................................................................................................................
Potential difference = ............................................. V
(2)
(b)
Calculate the resistance of the resistor labelled R.
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
Resistance = ............................................. Ω
(3)
Page 5 of 26
(c)
State what happens to the total resistance of the circuit and the current through the circuit
when switch S is closed.
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
(2)
(Total 7 marks)
4
The picture shows an electric cooker hob. The simplified circuit diagram shows how the four
heating elements connect to the mains electricity supply. The heating elements are identical.
When all four heating elements are switched on at full power the hob draws a current of 26 A
from the 230 V mains electricity supply.
(a)
Calculate the resistance of one heating element when the hob is switched on at full power.
Give your answer to 2 significant figures.
........................................................................................................................
........................................................................................................................
........................................................................................................................
Resistance = .............................. Ω
(3)
Page 6 of 26
(b)
The table gives the maximum current that can safely pass through copper wires of different
cross-sectional area.
Cross-sectional
area in mm2
Maximum safe
current in amps
1.0
11.5
2.5
20.0
4.0
27.0
6.0
34.0
The power sockets in a home are wired to the mains electricity supply using cables
containing 2.5 mm2 copper wires. Most electrical appliances are connected to the mains
electricity supply by plugging them into a standard power socket.
It would not be safe to connect the electric cooker hob to the mains electricity supply by
plugging it into a standard power socket.
Why?
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
(2)
(c)
Mains electricity is an alternating current supply. Batteries supply a direct current.
What is the difference between an alternating current and a direct current?
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
(2)
(Total 7 marks)
Page 7 of 26
5
(a)
Draw one line from each circuit symbol to its correct name.
Circuit symbol
Name
Diode
Lightdependent
resistor
(LDR)
Lamp
Lightemitting
diode (LED)
(3)
Page 8 of 26
(b)
Figure 1 shows three circuits.
The resistors in the circuits are identical.
Each of the cells has a potential difference of 1.5 volts.
Figure 1
Circuit 1
(i)
Circuit 2
Circuit 3
Use the correct answer from the box to complete the sentence.
half
twice
the same as
The resistance of circuit 1 is ................................................ the resistance of circuit
3.
(1)
(ii)
Calculate the reading on voltmeter V2.
...............................................................................................................
Voltmeter reading V2 = .............................. V
(1)
(iii)
Which voltmeter, V1, V2 or V3, will give the lowest reading?
Draw a ring around the correct answer.
V1
V2
V3
(1)
Page 9 of 26
(c)
A student wanted to find out how the number of resistors affects the current in a series
circuit.
Figure 2 shows the circuit used by the student.
Figure 2
The student started with one resistor and then added more identical resistors to the circuit.
Each time a resistor was added, the student closed the switch and took the ammeter
reading.
The student used a total of 4 resistors.
Figure 3 shows three of the results obtained by the student.
Figure 3
Number of resistors in series
(i)
To get valid results, the student kept one variable the same throughout the
experiment.
Which variable did the student keep the same?
...............................................................................................................
(1)
Page 10 of 26
(ii)
The bar chart in Figure 3 is not complete. The result using 4 resistors is not shown.
Complete the bar chart to show the current in the circuit when 4 resistors were used.
(2)
(iii)
What conclusion should the student make from the bar chart?
...............................................................................................................
...............................................................................................................
(1)
(Total 10 marks)
6
The current in a circuit depends on the potential difference provided by the cells and the total
resistance of the circuit.
(a)
Figure 1 shows the graph of current against potential difference for a component.
What is the name of the component?
Draw a ring around the correct answer.
diode
filament bulb
thermistor
(1)
Page 11 of 26
(b)
Figure 2 shows a circuit containing a 6 V battery.
Two resistors, X and Y, are connected in parallel.
The current in some parts of the circuit is shown.
(i)
What is the potential difference across X?
Potential difference across X = ............................. V
(1)
(ii)
Calculate the resistance of X.
...............................................................................................................
...............................................................................................................
Resistance of X = ............................. Ω
(2)
Page 12 of 26
(iii)
What is the current in Y?
Current in Y = ............................. A
(1)
(iv)
Calculate the resistance of Y.
...............................................................................................................
Resistance of Y = ............................. Ω
(1)
(v)
When the temperature of resistor X increases, its resistance increases.
What would happen to the:
•
potential difference across X
•
current in X
•
total current in the circuit?
Tick ( ) three boxes.
Decrease
Stay the same
Increase
Potential difference across X
Current in X
Total current in the circuit
(3)
(Total 9 marks)
Page 13 of 26
7
(a)
Figure 1 shows the inside of a battery pack designed to hold three identical 1.5 V cells.
Figure 1
Which one of the arrangements shown in Figure 2 would give a 4.5 V output across the
battery pack terminals T?
Figure 2
(1)
(b)
Figure 3 shows a variable resistor and a fixed value resistor connected in series in a
circuit.
Figure 3
Complete Figure 3 to show how an ammeter would be connected to measure the current
through the circuit.
Use the correct circuit symbol for an ammeter.
(1)
Page 14 of 26
(c)
The variable resistor can be adjusted to have any value from 200 ohms to 600 ohms.
Figure 4 shows how the reading on voltmeter V1 and the reading on voltmeter V2 change
as the resistance of the variable resistor changes.
Figure 4
(i)
How could the potential difference of the battery be calculated from Figure 4?
Tick (✔) one box.
9 + 3 = 12 V
9–3=6V
9÷3=3V
Give the reason for your answer.
...................................................................................................................
...................................................................................................................
(2)
Page 15 of 26
(ii)
Use Figure 4 to determine the resistance of the fixed resistor, R.
Resistance of R = ..................... Ω
Give the reason for your answer.
...................................................................................................................
...................................................................................................................
(2)
(iii)
Calculate the current through the circuit when the resistance of the variable resistor
equals 200 Ω.
...................................................................................................................
...................................................................................................................
...................................................................................................................
Current = ..................... A
(3)
(Total 9 marks)
Page 16 of 26
Mark schemes
1
(a)
20
1
(b)
50
1
(c)
(i)
115
1
(ii)
230
1
(iii)
if one goes out the other still works
or
brighter
accept power (output) is greater
can be switched on/off independently is insufficient
1
(d)
the outside/casing is plastic
there is plastic around the wires is insufficient
it is plastic is insufficient
1
and plastic is an insulator
an answer the light fitting is double insulated gains both marks
1
(e)
(residual current) circuit breaker
accept RCCB
accept RCBO
accept RCCD
accept RCB
accept miniature circuit breaker / MCB
trip switch is insufficient
breaker is insufficient
do not accept earth wire
1
[8]
2
(a)
(i)
6
1
(ii)
variable resistor
1
(iii)
voltmeter
1
(b)
(i)
point at 3 V ringed
1
Page 17 of 26
(ii)
The student misread the ammeter.
1
(iii)
1 (volt)
accept every volt
1
(c)
as one increases so does the other
or
directly proportional
or
positive correlation
accept a numerical description, eg when one doubles the other also
doubles
1
[7]
3
(a)
V = 0.10 × 45
1
4.5 (V)
1
(b)
R = 12 / 0.10
1
total resistance = 120 (Ω)
1
R = 120 – 105 = 15 (Ω)
1
(c)
(total) resistance decreases
1
(so) current increases
1
[7]
4
(a)
35
an answer with more than 2 sig figs that rounds to 35 gains 2 marks
allow 2 marks for correct method, ie
allow 1 mark for I = 6.5 (A) or R =
an answer 8.8 gains 2 marks
an answer with more than 2 sig figs that rounds to 8.8 gains 1 mark
3
Page 18 of 26
(b)
(maximum) current exceeds maximum safe current for a 2.5 mm2 wire
accept power exceeds maximum safe power for a 2.5 mm2 wire
or
(maximum) current exceeds 20 (A)
(maximum) current = 26 (A) is insufficient
1
a 2.5 mm2 wire would overheat / melt
accept socket for wire
do not accept plug for wire
1
(c)
a.c. is constantly changing direction
accept a.c. flows in two directions
accept a.c. changes direction
a.c. travels in different directions is insufficient
1
d.c. flows in one direction only
1
[7]
Page 19 of 26
5
(a)
allow 1 mark for each correct line if more than one line is drawn
from any symbol then all of those lines are wrong
3
(b)
(i)
half
1
(ii)
3(V)
1
(iii)
V1
1
(c)
(i)
potential difference / voltage of the power supply
accept the power supply
accept the voltage / volts
accept number of cells / batteries
accept (same) cells / batteries
do not accept same ammeter / switch / wires
1
(ii)
bar drawn – height 1.(00)A
ignore width of bar
allow 1 mark for bar shorter than 3rd bar
2
(iii)
as the number of resistors increases the current decreases
1
[10]
6
(a)
filament bulb
1
Page 20 of 26
(b)
(i)
6V
1
(ii)
3 Ω or their
correctly calculated
allow 1 mark for correct substitution ie
6=2×R
or their (i) = 2 × R
2
(iii)
1A
1
(iv)
6 Ω or their (i) / their (iii) correctly calculated
1
(v)
Decrease
Stay the same
Increase
1
1
1
[9]
7
(a)
3rd box from the left ticked
1
(b)
correct symbol drawn in series with other components
symbol must have upper case A
1
(c)
(i)
9 + 3 = 12V
reason only scores if this mark scored
1
pd of battery is shared between the variable resistor and fixed resistor
accept V1 + V2 = pd of the battery
accept p.d. is shared in a series circuit
accept voltage for p.d.
1
Page 21 of 26
(ii)
600
reason only scores if this mark scored
1
p.d. of supply shared equally when resistors have the same value
or
ratio of the p.d. is the same as the ratio of the resistance
1
(iii)
0.015
or
their (c)(i) ÷ (their (c)(ii) + 200) correctly calculated
allow 2 marks for correct substitution ie 12 = I × 800
or
their (c)(i) = I × (their (c)(ii) + 200)
allow 1 mark for total resistance = 800 (Ω) or their (c)(ii) + 200
or
allow 1 mark for a substitution of 12 = I × 200
or
their (c)(i) = I × 200
or
alternative method using the graph
V = 3 V (1)
3 = I × 200 (1)
3
[9]
Page 22 of 26
Examiner reports
1
(a)
Only about one third of the students scored this mark. A common incorrect answer was
'40'.
(b)
Again only about one third of the students scored this mark. The most common answer
was '60'.
(c)
(i)
A significant number of the students did not attempt this question. About one third of
the students scored the mark.
(ii)
About a third of the students knew the potential difference would equal that of the
supply and so scored the mark.
(iii)
There were relatively few students who answered in terms of independent circuits i.e.
if one bulb goes out the other is unaffected. Those students who mentioned
increased brightness or increased power were successful. The majority of students
attempted to answer in terms of increased p.d. or current; or referred to p.d. or
current being the same for each bulb. Those who stated that both bulbs had the
same brightness failed to appreciate that this would also be true in a series circuit.
Few students scored this mark.
(d)
Over half of the students scored zero. There were too many students thinking that a light
fitting without an earth wire is safe because of the perceived dangers caused by an earth
wire. Others suggested that the neutral wire acted as an earth wire in this instance. Many
students had the idea of plastic being an insulator, although a surprising number stated it is
a conductor. It was relatively rare to see an unambiguous statement that the outside case
of the fitting is made of plastic. Some students were distracted by the insulation on the
individual wires.
(e)
A significant number of students did not attempt this question. Of those that did, few scored
the mark; the reference to a circuit breaker was rarely seen. A large number of the students
failed to read the question and gave 'fuse' as their answer. Other common incorrect
answers were insulation tape, plastic sockets, crocodile clips and plastic-covered wires.
Page 23 of 26
2
(a)
(b)
4
(i)
Most students gave the correct answer. Erroneous responses usually involved
dividing by 1.5.
(ii)
Nearly three quarters of students scored this mark.
(iii)
Nearly two thirds of students scored this mark. Incorrect responses were spread
equally between the other components joined in series.
(i)
Nearly all students now know what an anomalous result is and so scored this mark.
(ii)
Just under half of students realised that the most likely reason for the anomalous
result was a misreading of the ammeter.
(iii)
Many students clearly did not understand what was meant by the term ‘interval’. Most
students interpreted it as the range of p.d.’s or as the number of small squares on the
graph paper between readings or as the p.d. represented by the size of a small
square on the graph paper. Many students gave descriptions of what happened to
the current as the p.d. was changed.
(c)
This was well answered with a variety of acceptable phrases. Most students described an
increase in p.d. leading to an increase in the current. Some students went for a positive
correlation, with a few students giving directly proportional. Those students who tried to
answer in terms of numerical values were less successful as they often failed to read the
current scale correctly.
(a)
The correct answer of 35 was rarely given; 8.8 as the resistance for all 4 heating elements
was the most common answer. A number of students then incorrectly divided by 4 to find
the resistance of a single heating element. These students usually gained a single mark for
dividing the p.d. of 230 V by the current of 26 A. The concept of significant figures is still not
well understood with very few students scoring full marks.
(b)
Very few students scored both marks, however half of students did score one mark. Most
answers lacked detail and some made reference to potential difference rather than current.
Several students confused current and p.d, writing that 230 V was too high for the wire.
Surprisingly few students scored the mark for overheating with many references to plugs /
things blowing up and fuses melting rather than the wire.
(c)
Nearly half of students gained both marks. For direct current, frequent incorrect answers
included: ‘the current goes straight to the device’, or ‘straight to the source with no wires’,
‘direct current travels in straight lines’. With regard to alternating current incorrect answers
seen frequently included ‘alternating current goes up and down’, ‘only flows in a parallel
circuit’ or ‘goes in many directions.’
Page 24 of 26
5
(a)
This was well answered with three fifths of the students scoring all three marks. There
seemed no real pattern to the errors that were made.
(b)
(i)
Just over three fifths of the students scored this mark.
(ii)
Only just over half of the students were able to correctly add the potential differences
of the two cells. Many of the incorrect answers resulted from the students multiplying
the potential differences together.
(iii)
Nearly three fifths of the students scored this mark.
(i)
Only about a third of the students scored this mark. Many students failed to realise
that the bar graph indicated both the number of resistors and current had changed
and gave either of these quantities as the answer. Using the same ammeter was
another common incorrect answer. A minority of students stated that the control
variable does not change without actually identifying a control variable.
(ii)
A majority of the students could see the pattern of reducing current and scored one
mark for drawing a bar of reduced height. About a fifth of the students were able to
score the second mark by accurately drawing this bar at the value of 1.0 amps.
(iii)
Over four fifths of the students were able to express an answer in terms of ‘as the
number of resistors increases, the current decreases’. Common errors were to have
the two functions both increasing or both decreasing. Other unacceptable answers
were that the number of resistors changed or affected the current without writing in
which direction the change would be.
(c)
6
7
(a)
More than three-quarters of students correctly identified the component as the filament
bulb.
(b)
(i)
Around two-thirds of students gave the correct answer of 6 V. Of those who gave an
incorrect answer, many divided the supply voltage by 2 to give 3 V.
(ii)
Most students gained both marks.
(iii)
Most students were able to gain this mark.
(iv)
Again, this question was also answered well, with over three-quarters scoring the
mark.
(v)
Around half of the students scored two or three of the three available marks. The most
common error was to think that the potential difference across X would change.
(a)
Surprisingly less than half of the students answered this correctly.
(b)
Over two thirds of students answered this correctly. The symbol was almost universally
known. Some students added more than one ammeter but gained credit provided all were
correct. There were a number of students who connected the ammeter across the two
voltmeters.
(c)
(i)
Only a fifth of the students scored both marks. A significant number of the students
explained a choice of 6V by stating that (potential) difference means subtract so 9V –
3V = 6V.
Page 25 of 26
(ii)
A third of the students scored 1 mark for an answer of 600, but failed to explain the
reason successfully for the second mark. The most popular response simply referred
to the two lines meeting at 600.
(iii)
Very few students showed evidence of total resistance of 800 or their (c)(ii) + 200.
Many scored 1 mark for their (c)(i) (usually 6) divided by 200. There were, however, a
significant number who gave the correct answer, despite not choosing 12V for (c)(i).
providing evidence that many students were using the graph to answer this part of
the question.
Page 26 of 26