Particles and Nuclear Structures Unit 1.7

Question 1

Define antiparticle

Answer 1

subatomic particle with the same mass as a given particle but the opposite charge.

Question 2

Define Quark?

Answer 2

particle that experiences the strong nuclear force.

Question 3

Define Lepton?

Answer 3

particle that experiences the weak nuclear force(not strong)

Question 4

How many generations of particles are there?

Answer 4

3 generations

Question 5

Which generation was found first?

Answer 5

First one, 2nd and 3rd particles were discovered when more powerful particle accelerators became available.

Question 6

Antiparticles have same properties as the corresponding particle except…

Answer 6

charge is opposite

Question 7

mass of electron

Answer 7

9.11x10^-31 KG

Question 8

Charge of an electron

Answer 8

1.6x10^-19

Question 9

What is annihilation?

Answer 9

Process whereby all/nearly all mass is lost and converted to energy according to E = MC^2

Question 10

Example of annihilation?

Answer 10

occurs in atmosphere due to cosmic rays electron - positron annihilation energy converted to 2 photons.

Question 11

Define Hadrons

Answer 11

Composite particle made up of quarks and /or antiquarks

Question 12

Define Baryon

Answer 12

Composite particle made up of 3 quarks

Question 13

Define Antibaryon?

Answer 13

composite particle made up of 3 antiquarks

Question 14

define Meson?

Answer 14

composite particle made of a quark and an antiquark.

Question 15

Quark make up of a baryon

Answer 15

qqq

Question 16

Quark makeup of a Mesons

Answer 16

q anti q

Question 17

One stable baryon?

Answer 17

proton

Question 18

2 things about pions?

Answer 18

1. baryon no. = 0 (true for all measons)
2. Neutral pion 2 makeup : u anti u OR d anti d

Question 19

Neutrinos are…

Answer 19

elementary particles

Question 20

neutrinos charge?

Answer 20

0

Question 21

lepton number for electrons and electron neutrinos is

Answer 21

1

Question 22

lepton number for positrons and antielectron neutrinos

Answer 22

-1

Question 23

3 conservation laws

Answer 23

Charge, Lepton, Baryon

Question 24

4 forces of the universe

Answer 24

Gravitational, weak, Electromagnetic, strong

Question 25

Properties of strong interaction:

Answer 25

1. particle decay have short lifetimes 2. interaction likely to happen in a collision 3. all particles involved are hadrons 4. no change in quark flavour

Question 26

Properties of electromagnetic interaction

Answer 26

1. particle decay have short lifetimes 2. all particles involved are charged 3. reaction unlikely to occur when a collision 4. 1 or more photons may be emitted 5. no change in quark flavour

Question 27

Properties of weak interactions.

Answer 27

1. particle decay have long lifetimes 2. neutrinos are involved 3. may be a change in quark flavour 4. unlikely to happen when 2 particles collide