Particle physics

Question 1

Nucleus

Answer 1

Nucleon number = mass no= protons + neutrons

proton no = atomic no = protons

Question 2

Isotopes

Answer 2

Same protons different neutrons

Question 3

Atomic mass unit

Answer 3

u, 1.661 x10^-27, 1/12th of C-12

Question 4

Hadrons

Answer 4

Protons, neutrons
Affected by strong nuclear force
Decay by weak nuclear force (beta)
Experience electromagnetic force

Question 5

Leptons

Answer 5

Electrons, neutrinos
Not affected by strong nuclear force
Experience electromagnetic force

Question 6

Quarks

Answer 6

All hadrons are made of quarks
Protons- udu
Neutrons- dud

Question 7

Beta decay

Answer 7

Weak nuclear force

Negative:
Neutron to proton + electron + anti neutrino

Positive:
Proton to neutron + positron + neutrino

Question 8

Annihilation of anti matter and matter

Answer 8

Photon released

Use Einstein and de Broglie wavelength equations to find wavelength of photon

Question 9

Alpha particle scattering experiment

Answer 9

Most straight through = gold atom is mainly empty space
Some deflected at large angles = centre has a high positive charge
Few deflected greater than 90• = nucleus is small
In vacuum

Question 10

Strong nuclear force

Answer 10

Holds nucleus together

>3fm 
SNF is weak
3-0.5fm 
SNF > electrostatic force
<0.5fm
Repulsive

Question 11

Half life

Answer 11

Average time for 1/2 of neutrons in sample to decay

Question 12

Binding energy

Answer 12

Minimum energy needed to separate all protons and neutrons to infinity

Mass of nucleus less than mass of nucleons