Monday 8 June 2026 – Morning
A Level Physics A
H556/03 Unified physics
Time allowed: 1 hour 30 minutes
You must have:
* 2 6 7 8 1 6 1 9 3 7 *
• the Data, Formulae and Relationships Booklet
You can use:
• a scientific or graphical calculator
• a ruler (cm/mm)
* H 5 5 6 0 3 *
Please write clearly in black ink. Do not write in the barcodes.
Centre number Candidate number
First name(s)
Last name
INSTRUCTIONS
• Use black ink. You can use an HB pencil, but only for graphs and diagrams.
• Write your answer to each question in the space provided. If you need extra space use
the lined pages at the end of this booklet. The question numbers must be clearly shown.
• Answer all the questions.
• Where appropriate, your answers should be supported with working. Marks might be
given for using a correct method, even if your answer is wrong.
INFORMATION
• The total mark for this paper is 70.
• The marks for each question are shown in brackets [ ].
• Quality of extended response will be assessed in questions marked with an asterisk (*).
• This document has 24 pages.
ADVICE
• Read each question carefully before you start your answer.
© Cambridge OCR 2026 [601/4743/X] Cambridge OCR is an exempt Charity
DC (DE/SG) 368104/5 Turn over
, 2
1 The diagram shows an electrical panel heater with the front panel removed. The front panel is
attached when the heater is in use.
Resistance
wire
300 mm
Front
panel
600 mm
To mains
supply
The resistance wire heats the front panel. The front panel emits infrared radiation.
(a) The table shows data for this heater.
Input potential difference (p.d.) / V 230
Input power / W 200
Length of resistance wire / m 10
Resistivity of resistance wire / Ωm 4.9 × 10–7
The resistance wire has a circular cross-section and a constant diameter.
Calculate the diameter of the wire.
Diameter = ...................................................... m [4]
© Cambridge OCR 2026
, 3
(b) The energy radiated per unit time P from the front panel can be calculated using the equation:
P = 0.9AσT 4
where:
• A is the surface area of the front panel in m2
• T is the surface temperature in K
• σ is the Stefan constant, 5.67 × 10–8 W m–2 K–4.
The front panel measures 600 mm × 300 mm. The surface temperature of the front panel
is 90.0 °C.
Calculate the energy radiated per unit time from the front panel.
Give your answer to 2 significant figures.
Energy radiated per unit time = ...................................................... W [4]
(c) Suggest why the heater transfers more energy per unit time than your answer to (b).
..........................................................................................................................................................
..................................................................................................................................................... [1]
© Cambridge OCR 2026 Turn over
A Level Physics A
H556/03 Unified physics
Time allowed: 1 hour 30 minutes
You must have:
* 2 6 7 8 1 6 1 9 3 7 *
• the Data, Formulae and Relationships Booklet
You can use:
• a scientific or graphical calculator
• a ruler (cm/mm)
* H 5 5 6 0 3 *
Please write clearly in black ink. Do not write in the barcodes.
Centre number Candidate number
First name(s)
Last name
INSTRUCTIONS
• Use black ink. You can use an HB pencil, but only for graphs and diagrams.
• Write your answer to each question in the space provided. If you need extra space use
the lined pages at the end of this booklet. The question numbers must be clearly shown.
• Answer all the questions.
• Where appropriate, your answers should be supported with working. Marks might be
given for using a correct method, even if your answer is wrong.
INFORMATION
• The total mark for this paper is 70.
• The marks for each question are shown in brackets [ ].
• Quality of extended response will be assessed in questions marked with an asterisk (*).
• This document has 24 pages.
ADVICE
• Read each question carefully before you start your answer.
© Cambridge OCR 2026 [601/4743/X] Cambridge OCR is an exempt Charity
DC (DE/SG) 368104/5 Turn over
, 2
1 The diagram shows an electrical panel heater with the front panel removed. The front panel is
attached when the heater is in use.
Resistance
wire
300 mm
Front
panel
600 mm
To mains
supply
The resistance wire heats the front panel. The front panel emits infrared radiation.
(a) The table shows data for this heater.
Input potential difference (p.d.) / V 230
Input power / W 200
Length of resistance wire / m 10
Resistivity of resistance wire / Ωm 4.9 × 10–7
The resistance wire has a circular cross-section and a constant diameter.
Calculate the diameter of the wire.
Diameter = ...................................................... m [4]
© Cambridge OCR 2026
, 3
(b) The energy radiated per unit time P from the front panel can be calculated using the equation:
P = 0.9AσT 4
where:
• A is the surface area of the front panel in m2
• T is the surface temperature in K
• σ is the Stefan constant, 5.67 × 10–8 W m–2 K–4.
The front panel measures 600 mm × 300 mm. The surface temperature of the front panel
is 90.0 °C.
Calculate the energy radiated per unit time from the front panel.
Give your answer to 2 significant figures.
Energy radiated per unit time = ...................................................... W [4]
(c) Suggest why the heater transfers more energy per unit time than your answer to (b).
..........................................................................................................................................................
..................................................................................................................................................... [1]
© Cambridge OCR 2026 Turn over
