Materials
For this paper you must have:
• a pencil and a ruler
• a scientific calculator
• a Data and Formulae Booklet
• a
... [Show More] protractor.
Instructions
• Use black ink or black ball-point pen.
• Fill in the boxes at the top of this page.
• Answer all questions.
• You must answer the questions in the spaces provided. Do not write
outside the box around each page or on blank pages.
• 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).
• Do all rough work in this book. Cross through any work you do not want
to be marked.
• Show all your working.
Information
• The marks for questions are shown in brackets.
• The maximum mark for this paper is 70.
• You are expected to use a scientific calculator where appropriate.
• A Data and Formulae Booklet is provided as a loose insert.
Please write clearly in block capitals.
Centre number Candidate number
Surname
Forename(s)
Candidate signature
I declare this is my own work.
AS
PHYSICS
Paper 1
2
*02*
IB/M/Jun21/7407/1
Answer all questions in the spaces provided.
0 1 . 1 Identify the number of neutrons in a nucleus of polonium-210 ( ) 210Po 84 .
Tick () one box.
[1 mark]
84
126
210
294
0 1 . 2 A polonium-210 nucleus is formed when a stationary nucleus of bismuth-210 decays.
A beta-minus (β−
) particle is emitted in this decay.
Outline, with reference to β− decay, why bismuth-210 and polonium-210 have different
proton numbers.
[2 marks]
Do not write
outside the
box
3
*03*
Turn over ►
IB/M/Jun21/7407/1
Do not write
outside the
box The kinetic energies of β− particles emitted from a sample of bismuth-210 are
analysed. These β− particles have a range of kinetic energies.
The total energy released when each nucleus of bismuth-210 decays to a
nucleus of polonium-210 is 1.2 MeV.
Figure 1 shows the variation with Ek of the number of β− particles that have the kinetic
energy Ek.
Figure 1
0 1 . 3 Explain how the data in Figure 1 support the hypothesis that a third particle is
produced during β− decay.
[2 marks]
Question 1 continues on the next page
4
*04*
IB/M/Jun21/7407/1
Do not write
outside the
0 1 box . 4 This third particle is an electron antineutrino.
Explain why an electron antineutrino, rather than an electron neutrino, is produced
during β− decay.
[2 marks]
0 1 . 5 A large tank of water is used as part of an electron antineutrino detector.
An electron antineutrino ν�e enters the tank and interacts with a proton (p).
Figure 2 represents this interaction.
Figure 2
Identify X and Y.
[2 marks]
X =
Y =
5
*05*
Turn over ►
IB/M/Jun21/7407/1
Do not write
outside the
0 1 box . 6 The positron produced in the interaction in Figure 2 slows down and collides with a
lepton in a molecule of water.
Describe the process that occurs when the positron collides with this lepton.
In your answer you should identify the lepton in the molecule of water. [Show Less]