Particle Physics 💥

Question 1

What is the plum pudding model?

Answer 1

A model of the atom which suggests the atom is a sphere of positive charge with negative electrons embedded within it.

Question 2

What were the observations and conclusions of Rutherford’s alpha particle scattering experiment?

Answer 2

Most of the alpha particles passed straight through the foil -> atom is mostly empty space, mass concentrated in small region at centre.

A small number of alpha particles were deflected through angles of more than 90* -> nucleus has positive charge

Question 3

What is the approximate radius of a nuclues?

Answer 3

10^-14m

Question 4

What is the approximate radius of an atom?

Answer 4

10^-10m

Question 5

What are isotopes?

Answer 5

Nuclei of the same element that have the same number of protons but different numbers of neutrons.

Question 6

What is protium?

Answer 6

A hydrogen nucleus with 1 proton and 0 neutrons.

Question 7

What is deuterium?

Answer 7

A hydrogen nucleus with 1 proton and 1 neutron.

Question 8

What is tritium?

Answer 8

A hydrogen nucleus with 1 proton and 2 neutrons.

Question 9

For what range is the strong nuclear force attractive?

Answer 9

0.5fm<x<3fm

Question 10

For what range is the strong nuclear force repulsive?

Answer 10

x<0.5fm

Question 11

What is a hadron?

Answer 11

A particle or antiparticle that experiences the strong nuclear force.

Question 12

What is a lepton?

Answer 12

A particle or antiparticle that does not experience the strong nuclear force.

Question 13

Give an example of a hadron

Answer 13

Protons, neutrons, mesons

Question 14

Give an example of a lepton

Answer 14

Electrons, neutrinos, muons

Question 15

What is a fundamental particle?

Answer 15

A particle that has no internal structure and hence cannot be divided into smaller sub components.

Question 16

What is the quark composition of a proton?

Answer 16

uud

Question 17

What is the quark composition of a neutron?

Answer 17

udd

Question 18

What is a baryon?

Answer 18

A hadron made up of three quarks and/or antiquarks.

Question 19

What is a meson?

Answer 19

A hadron made of a quark and an antiquark.

Question 20

Describe beta minus decay in terms of quarks

Answer 20

A down quark turns into an up quark, producing an electron and an antineutrino.

Question 21

Describe beta minus decay in terms of protons and neutrons

Answer 21

A neutron turns into a proton producing an electron and an antineutrino.

Question 22

Describe beta plus decay in terms of quarks

Answer 22

An up quark turns into a down quark producing a positron and a neutrino.

Question 23

Describe beta plus decay in terms of protons and neutrons

Answer 23

A proton turns into a neutron producing a positron and a neutrino.

Question 24

What is a neutrino?

Answer 24

A very small (effectively massless) chargeless particle that due to its small mass and no charge very rarely interacts with matter.

Question 25

List 3 quantities conserved in beta decay

Answer 25

Charge, momentum, mass-energy, baryon number

Question 26

What is the baryon number of a quark?

Answer 26

+1/3 (same for up, down and strange)

Question 27

What is the baryon number of an antiquark?

Answer 27

-1/3 (same for up, down and strange)