Please write clearly in block capitals.
Centre number Candidate number
A-level
Surname
Forename(s)
PHYSICS
Candidate signature
I declare this is my own work.
7408/3BB
Paper 3 Section B Medical physics
A-level Mark scheme
PHYSICS June 2026
Paper 3 Version: 1.0 Final
Section B Medical physics
Monday 8 June 2026 Morning Time allowed: The total time for
both sections of this paper is
Materials
2 hours. You are advised to
For this paper you must have:
• a pencil and a ruler spend approximately
• a scientific calculator 50 minutes on this section.
• a Data and Formulae Booklet
• a protractor.
Instructions For Examiner’s Use
• Use black ink or black ball-point pen.
Question Mark
• Fill in the boxes at the top of this page.
• Answer all questions. 1
• You must answer the questions in the spaces provided. Do not write 2
outside the box around each page or on blank pages.
3
• If you need extra space for your answer(s), use the lined pages at the end of
this book. Write the question number against your answer(s). 4
• Do all rough work in this book. Cross through any work you do not want 5
to be marked.
TOTAL
• Show all your working.
Information
• The marks for questions are shown in brackets.
• The maximum mark for this paper is 35.
• You are expected to use a scientific calculator where appropriate.
• A Data and Formulae Booklet is provided as a loose insert.
*jun2674083BB01*
IB/M/Jun26/G4007/V8 7408/3BB
, 2
MARK SCHEME – A-LEVEL PHYSICS – 7408/3BB – JUNE 2026
Do not write
outside the
Section B box
Mark schemes are prepared by the Lead Assessment Writer and considered, together with the relevant
Answer all questions in this section.
questions, by a panel of subject teachers. This mark scheme includes any amendments made at the
standardisation events which all associates participate in and is the scheme which was used by them in
this examination. The standardisation process ensures that the mark scheme covers the students’
0 1 A person’s eye has a maximum refractive power of +48 D.
responses to questions and that every associate understands and applies it in the same correct way.
A glass lens of power +48 D is used to model the person’s eye.
As preparation for standardisation each associate analyses a number of students’ scripts. Alternative
answers not already covered by the mark scheme are discussed and legislated for. If, after the
0 1 . 1 The distance between the glass lens and an object is 250 mm. standardisation process, associates encounter unusual answers which have not been raised they are
required to refer these to the Lead Examiner.
Show that the distance from the glass lens to the image is about 23 mm.
[1 mark] It must be stressed that a mark scheme is a working document, in many cases further developed and
expanded on the basis of students’ reactions to a particular paper. Assumptions about future mark
schemes on the basis of one year’s document should be avoided; whilst the guiding principles of
assessment remain constant, details will change, depending on the content of a particular examination
paper.
No student should be disadvantaged on the basis of their gender identity and/or how they refer to the
gender identity of others in their exam responses.
The length of the person’s eyeball is 22 mm. A consistent use of ‘they/them’ as a singular and pronouns beyond ‘she/her’ or ‘he/him’ will be credited in
The person uses a correcting lens to focus on an object that is 250 mm from their eye. exam responses in line with existing mark scheme criteria.
0 1 . 2 State and explain the defect of vision for this eye.
[2 marks] Further copies of this mark scheme are available from
0 1 . 3 Deduce the minimum power of this correcting lens.
[3 marks]
information
retains the on all its publications. However, registered schools/colleges for are permitted to copy material from this booklet for their own
minimum power = D internal use, with the following important exception: cannot give permission to schools/colleges to photocopy any material that is acknowledged to a third
party even for internal use within the centre.
and its licensors. All rights reserved.
*02*
2
IB/M/Jun26/7408/3BB
, 3
MARK SCHEME – A-LEVEL PHYSICS – 7408/3BB – JUNE 2026
Do not write
outside the
0 1 . 4 Figure 1 shows how the person can avoid using the correcting lens but still see box
things clearly.
Physics - Mark scheme instructions to examiners
The person views some text through a small hole made by their fingers.
Figure 1 1. General
The mark scheme for each question shows:
• the marks available for each part of the question
• the total marks available for the question
• the typical answer or answers which are expected
• extra information to help the Examiner make his or her judgement and help to delineate what is
acceptable or not worthy of credit or, in discursive answers, to give an overview of the area in which a
mark or marks may be awarded.
The extra information is aligned to the appropriate answer in the left-hand part of the mark scheme and
should only be applied to that item in the mark scheme.
At the beginning of a part of a question a reminder may be given, for example: where consequential
The eye focuses the light from the text onto the fovea. marking needs to be considered in a calculation; or the answer may be on the diagram or at a different
place on the script.
Suggest why the method shown in Figure 1 works best when the text is brightly lit.
[2 marks] In general the right-hand side of the mark scheme is there to provide those extra details which confuse
the main part of the mark scheme yet may be helpful in ensuring that marking is straightforward and
consistent.
2. Emboldening
2.1
In a list of acceptable answers where more than one mark is available ‘any two from’ is used, with the
number of marks emboldened. Each of the following bullet points is a potential mark.
2.2
8 A bold and is used to indicate that both parts of the answer are required to award the mark.
2.3
Alternative answers acceptable for a mark are indicated by the use of or. Different terms in the mark
scheme are shown by a / ; eg allow smooth / free movement.
3. Marking points
Turn over for the next question
3.1 Marking of lists
This applies to questions requiring a set number of responses, but for which candidates have provided
extra responses. The general principle to be followed in such a situation is that ‘right + wrong = wrong’.
Each error/contradiction negates each correct response. So, if the number of errors/contradictions
equals or exceeds the number of marks available for the question, no marks can be awarded.
However, responses considered to be neutral (often prefaced by ‘Ignore’ in the mark scheme) are not
penalised.
Turn over ►
*03*
3
IB/M/Jun26/7408/3BB
Centre number Candidate number
A-level
Surname
Forename(s)
PHYSICS
Candidate signature
I declare this is my own work.
7408/3BB
Paper 3 Section B Medical physics
A-level Mark scheme
PHYSICS June 2026
Paper 3 Version: 1.0 Final
Section B Medical physics
Monday 8 June 2026 Morning Time allowed: The total time for
both sections of this paper is
Materials
2 hours. You are advised to
For this paper you must have:
• a pencil and a ruler spend approximately
• a scientific calculator 50 minutes on this section.
• a Data and Formulae Booklet
• a protractor.
Instructions For Examiner’s Use
• Use black ink or black ball-point pen.
Question Mark
• Fill in the boxes at the top of this page.
• Answer all questions. 1
• You must answer the questions in the spaces provided. Do not write 2
outside the box around each page or on blank pages.
3
• If you need extra space for your answer(s), use the lined pages at the end of
this book. Write the question number against your answer(s). 4
• Do all rough work in this book. Cross through any work you do not want 5
to be marked.
TOTAL
• Show all your working.
Information
• The marks for questions are shown in brackets.
• The maximum mark for this paper is 35.
• You are expected to use a scientific calculator where appropriate.
• A Data and Formulae Booklet is provided as a loose insert.
*jun2674083BB01*
IB/M/Jun26/G4007/V8 7408/3BB
, 2
MARK SCHEME – A-LEVEL PHYSICS – 7408/3BB – JUNE 2026
Do not write
outside the
Section B box
Mark schemes are prepared by the Lead Assessment Writer and considered, together with the relevant
Answer all questions in this section.
questions, by a panel of subject teachers. This mark scheme includes any amendments made at the
standardisation events which all associates participate in and is the scheme which was used by them in
this examination. The standardisation process ensures that the mark scheme covers the students’
0 1 A person’s eye has a maximum refractive power of +48 D.
responses to questions and that every associate understands and applies it in the same correct way.
A glass lens of power +48 D is used to model the person’s eye.
As preparation for standardisation each associate analyses a number of students’ scripts. Alternative
answers not already covered by the mark scheme are discussed and legislated for. If, after the
0 1 . 1 The distance between the glass lens and an object is 250 mm. standardisation process, associates encounter unusual answers which have not been raised they are
required to refer these to the Lead Examiner.
Show that the distance from the glass lens to the image is about 23 mm.
[1 mark] It must be stressed that a mark scheme is a working document, in many cases further developed and
expanded on the basis of students’ reactions to a particular paper. Assumptions about future mark
schemes on the basis of one year’s document should be avoided; whilst the guiding principles of
assessment remain constant, details will change, depending on the content of a particular examination
paper.
No student should be disadvantaged on the basis of their gender identity and/or how they refer to the
gender identity of others in their exam responses.
The length of the person’s eyeball is 22 mm. A consistent use of ‘they/them’ as a singular and pronouns beyond ‘she/her’ or ‘he/him’ will be credited in
The person uses a correcting lens to focus on an object that is 250 mm from their eye. exam responses in line with existing mark scheme criteria.
0 1 . 2 State and explain the defect of vision for this eye.
[2 marks] Further copies of this mark scheme are available from
0 1 . 3 Deduce the minimum power of this correcting lens.
[3 marks]
information
retains the on all its publications. However, registered schools/colleges for are permitted to copy material from this booklet for their own
minimum power = D internal use, with the following important exception: cannot give permission to schools/colleges to photocopy any material that is acknowledged to a third
party even for internal use within the centre.
and its licensors. All rights reserved.
*02*
2
IB/M/Jun26/7408/3BB
, 3
MARK SCHEME – A-LEVEL PHYSICS – 7408/3BB – JUNE 2026
Do not write
outside the
0 1 . 4 Figure 1 shows how the person can avoid using the correcting lens but still see box
things clearly.
Physics - Mark scheme instructions to examiners
The person views some text through a small hole made by their fingers.
Figure 1 1. General
The mark scheme for each question shows:
• the marks available for each part of the question
• the total marks available for the question
• the typical answer or answers which are expected
• extra information to help the Examiner make his or her judgement and help to delineate what is
acceptable or not worthy of credit or, in discursive answers, to give an overview of the area in which a
mark or marks may be awarded.
The extra information is aligned to the appropriate answer in the left-hand part of the mark scheme and
should only be applied to that item in the mark scheme.
At the beginning of a part of a question a reminder may be given, for example: where consequential
The eye focuses the light from the text onto the fovea. marking needs to be considered in a calculation; or the answer may be on the diagram or at a different
place on the script.
Suggest why the method shown in Figure 1 works best when the text is brightly lit.
[2 marks] In general the right-hand side of the mark scheme is there to provide those extra details which confuse
the main part of the mark scheme yet may be helpful in ensuring that marking is straightforward and
consistent.
2. Emboldening
2.1
In a list of acceptable answers where more than one mark is available ‘any two from’ is used, with the
number of marks emboldened. Each of the following bullet points is a potential mark.
2.2
8 A bold and is used to indicate that both parts of the answer are required to award the mark.
2.3
Alternative answers acceptable for a mark are indicated by the use of or. Different terms in the mark
scheme are shown by a / ; eg allow smooth / free movement.
3. Marking points
Turn over for the next question
3.1 Marking of lists
This applies to questions requiring a set number of responses, but for which candidates have provided
extra responses. The general principle to be followed in such a situation is that ‘right + wrong = wrong’.
Each error/contradiction negates each correct response. So, if the number of errors/contradictions
equals or exceeds the number of marks available for the question, no marks can be awarded.
However, responses considered to be neutral (often prefaced by ‘Ignore’ in the mark scheme) are not
penalised.
Turn over ►
*03*
3
IB/M/Jun26/7408/3BB
