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A LEVEL UNIFIED PHYSICS A
H556/03 JUNE 2018 QUESTION
PAPER AND MARK SCHEME
REVISED AND REVIEWED
Answer all the questions
1 This question is about a resistance wire made of nichrome.
(a) * It is suggested that the resistance R of a length of nichrome wire varies with temperature θ
in °C according to the equation
R = R0 (1 + kθ)
where R0 is the resistance of the wire at 0 °C and k is a constant for the wire.
Fig. 1.1 shows a diagram of the arrangement of apparatus in an experiment to test the
relationship between R and θ and to determine the value of k.
thermometer
A
d.c. supply V
nichrome
wire
water
beaker
heat
Fig. 1.1
The resistance wire is coiled and placed in a water bath.
Describe how you would carry out the experiment, analyse the data to verify the relationship
between R and θ and determine a value for k.
In your description, state any precautions that you would take to improve the accuracy and
precision of the measurements.
© OCR 2018
, 3
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Question 1 is continued on page 4.
© OCR 2018 Turn over
, 4
(b) A student is investigating a 230 V, 1.0 kW heating element. The heating element is shown in
Fig. 1.2.
18 cm
1.4 cm
Fig. 1.2
A length of nichrome wire is wound in a spiral groove along 18 cm of a ceramic cylinder of
diameter 1.4 cm. The distance between the centres of adjacent turns of the wire is 1.5 mm.
The numbers labelling the reels of loose wire on the laboratory shelf are the imperial standard
wire gauge (swg). The student wishes to find out which reel holds the same wire as that
wound on the heating element of Fig. 1.2.
The book of data gives the following information:
resistivity of nichrome at operating temperature = 1.1 × 10−6 Ω m
swg 24 26 28 30 32
diameter of wire / 10−3 m 0.56 0.46 0.38 0.32 0.27
cross-sectional area / 10−6 m2 0.25 0.16 0.11 0.08 0.06
(i) Show that the resistance of the nichrome wire wound on the ceramic cylinder is 53 Ω.
[2]
© OCR 2018
, 5
(ii) Show that the length of wire wound on the heating element is 5.3 m.
[2]
(iii) Use the information given in (i) and (ii) to determine the swg number of the wire used as
the heating element.
swg number = .................................................................. [3]
© OCR 2018 Turn over
A LEVEL UNIFIED PHYSICS A
H556/03 JUNE 2018 QUESTION
PAPER AND MARK SCHEME
REVISED AND REVIEWED
Answer all the questions
1 This question is about a resistance wire made of nichrome.
(a) * It is suggested that the resistance R of a length of nichrome wire varies with temperature θ
in °C according to the equation
R = R0 (1 + kθ)
where R0 is the resistance of the wire at 0 °C and k is a constant for the wire.
Fig. 1.1 shows a diagram of the arrangement of apparatus in an experiment to test the
relationship between R and θ and to determine the value of k.
thermometer
A
d.c. supply V
nichrome
wire
water
beaker
heat
Fig. 1.1
The resistance wire is coiled and placed in a water bath.
Describe how you would carry out the experiment, analyse the data to verify the relationship
between R and θ and determine a value for k.
In your description, state any precautions that you would take to improve the accuracy and
precision of the measurements.
© OCR 2018
, 3
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. ............................................................................................................................................................ [6]
Question 1 is continued on page 4.
© OCR 2018 Turn over
, 4
(b) A student is investigating a 230 V, 1.0 kW heating element. The heating element is shown in
Fig. 1.2.
18 cm
1.4 cm
Fig. 1.2
A length of nichrome wire is wound in a spiral groove along 18 cm of a ceramic cylinder of
diameter 1.4 cm. The distance between the centres of adjacent turns of the wire is 1.5 mm.
The numbers labelling the reels of loose wire on the laboratory shelf are the imperial standard
wire gauge (swg). The student wishes to find out which reel holds the same wire as that
wound on the heating element of Fig. 1.2.
The book of data gives the following information:
resistivity of nichrome at operating temperature = 1.1 × 10−6 Ω m
swg 24 26 28 30 32
diameter of wire / 10−3 m 0.56 0.46 0.38 0.32 0.27
cross-sectional area / 10−6 m2 0.25 0.16 0.11 0.08 0.06
(i) Show that the resistance of the nichrome wire wound on the ceramic cylinder is 53 Ω.
[2]
© OCR 2018
, 5
(ii) Show that the length of wire wound on the heating element is 5.3 m.
[2]
(iii) Use the information given in (i) and (ii) to determine the swg number of the wire used as
the heating element.
swg number = .................................................................. [3]
© OCR 2018 Turn over
