Particle Physics

Question 1

Lead box with slit (experiment)

Answer 1

• To ensure a single path for alpha particles
• Alpha particles are absorbed by lead

Question 2

Vacuum (experiment)

Answer 2

• To ensure sufficient alpha particles reach the foil
• Because alpha particles would collide with air molecules

Question 3

Zinc sulphide screen

Answer 3

• Scintillates (emits light) when the alpha particles hit it
• to detect the particles and their direction

Question 4

Most of the alpha particles were undeflected (analysis)

Answer 4

Most did not get near enough to any matter or charge to be affected

Question 5

Most of the alpha particles were deflected (conclusion)

Answer 5

The atom is mostly empty space

Question 6

A few particles were deflected (analysis)

Answer 6

Only a few particles came close enough to charge to be deflected

Question 7

A few particles were deflected (conclusion)

Answer 7

The atom contains a small region of highly concentrated charge

Question 8

A very small proportion of alpha particles were deflected through more than 90 (analysis)

Answer 8

An area of the atom must have mass much greater than the alpha particle mass to cause this deflection

Question 9

A very small proportion of alpha particles were deflected through more than 90 (conclusion)

Answer 9

Most of the mass of the atom is concentrated in a very small space relative to the size of the atom

Question 10

Quark (gen 1)

Answer 10

• up (+2/3)
• down (+2/3)

Question 11

Quark (gen 2)

Answer 11

• Charm (+2/3)
• Strange (-1/3)

Question 12

Quark (gen 3)

Answer 12

• Top (+2/3)
• Bottom (-1/3)

Question 13

Leptons (gen 1)

Answer 13

• Electron (-1)
• Electron neutrino (0)

Question 14

Leptons (gen 2)

Answer 14

• Muon (-1)
• Muon neutrino (0)

Question 15

Leptons (gen 3)

Answer 15

• tau (-1)
• tau neutrino (0)

Question 16

Quarks

Answer 16

A quark is a type of fundamental particle. Quarks combine to form composite particles called hadrons,
the most stable of which are protons and neutrons.

Question 17

Lepton

Answer 17

A lepton is an fundamental particle that does not undergo strong interactions. It always exists alone

Question 18

Antimatter

Answer 18

material composed of antiparticles, which have the same mass as particles of ordinary matter but opposite charges, as well as other particle properties such as lepton and baryon numbers and quantum spin

Question 19

Describe what happens when matter and antimatter meet? (2 Marks)

Answer 19

• Annihilate each other
• Gamma rays (high energy photons) given off

Question 20

Explain why it is difficult to store antimatter? (2 marks)

Answer 20

• When it touches matter (the sides of the container)
• Annihilate each other

Question 21

Hadrons

Answer 21

• BARYONS (proton and neutron)
• MESONS (pion and kaon)

Question 22

Baryon

Answer 22

Is a composite subatomic particle made up of three quarks, bound together by the strong interactions

Question 23

Mesons

Answer 23

subatomic particles composed of one quark and one antiquark, bound together by the strong interaction

Question 24

What needs to be conserved during nuclear reactions:

Answer 24

• Momentum
• Charge
• Baryon number
• Lepton number

Question 25

Baryon number of baryon(proton, neutron, sigma)

Answer 25

+1

Question 26

Baryon number of baryon antiparticle (antiproton)

Answer 26

-1

Question 27

Baryon number of mesons (pion, kaon)

Answer 27

0

Question 28

Baryon number of leptons (electron, positron)

Answer 28

0

Question 29

Lepton numbers:

Answer 29

• Lepton +1
• Antilepton -1
• Other particle 0