Section 1 - Particles and Radiation Exam Questions Flashcards Preview

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Flashcards in Section 1 - Particles and Radiation Exam Questions Deck (54)
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1

Describe how the strong nuclear force between two nucleons varies with separation (2)

Repulsive then attractive above 1 fm
Short range

2

What is the nature of an alpha particle? (1)

Helium nucleus

3

Define isotopes (1)

Same atomic number
Different number of neutrons

4

Define nucleon number (1)

Number of protons and neutrons

5

Define proton number (1)

Number of protons

6

What term is used to describe an atom with one removed electron? (1)

Positive ion

7

Why would an alpha particle outside the nucleus be unaffected by the strong nuclear force? (2)

Strong nuclear force has a short range
No effect at distances above 3fm

8

Which constituent of an atom has the largest specific charge? (1)

Electron

9

What is the term given to a photon being converted into an electron and a positron? (1)

Pair production

10

Why is there a minimum energy for a photon to undergo pair production? (1)

Photon must provide enough energy to provide for the rest mass

11

What happens to extra energy from a photon during pair production? (1)

Provides the formed particles with kinetic energy

12

Which fundamental force is responsible for β+ decay? (1)

Weak force

13

What occurs in positron emmision? (2)

A proton forms a neutron and gives out a W+ boson that then decays into a positron and electron neutrino.

14

What is the virtual exchange particle used by electromotive force? (1)

Photon

15

What are the three differences between the exchange particles for weak and electromagnetic forces? (3)

Photon is massless
Photon has infinite range
Photon does not carry charge

16

Define an antiparticle (1)

All properties are opposite except mass

17

State the quark composition of a meson (1)

Quark
Antiquark

18

In weak decay, what property is not conserved? (1)

Strangeness

19

Explain electron capture (3)

An orbital electron interacts with a proton in the nucleus, a neutron is formed and a neutrino is released.

20

What roles can exchange particles have? (3)

Transfer energy
Transfer momentum
Transfer force

21

What does a strange particle have different to a particle that is not strange? (1)

It contains a strange quark

22

What is the most stable hadron? (1)

Proton

23

State a difference between a muon and an electron (1)

Mass

24

State a difference between hadrons and leptons (1)

Leptons do not experience the strong interaction but hadrons do

25

What are the two hadron groups and the difference between them? (3)

Baryons and Mesons
Baryons made from 3 quarks/antiquarks
Mesons made from quark antiquark pair

26

Why does the kinetic energy of emitted electrons have a maximum value? (2)

hf is energy available
Energy required to remove the electron varies

27

If frequency of radiation is below a value, why are electrons not emitted? (2)

Work function is the minimum energy needed to release an electron
Below a certain frequency, energy of a photon is less than work function

28

As time delay for electron emission from a metal surface does not occur, how did this lead to a particle model for light? (2)

Light travels as particles
They transfer energy in discrete packets

29

Explain what is meant by threshold frequency in reference to photon energy and intensity (3)

Threshold frequency is the minumum frequency for emission of electrons
If frequency is below threshold frequency, no emission even if intensity increased because photon energy is less than work function.

30

State and explain the effect on emitted electrons of increasing the frequency of incident light (2)

Maximum kinetic energy of released electrons increases
Because increasing frequency, increases photon's energy