particles and radiation

What is the diameter of a nucleus?

1 femtometre

What is the diameter of an atom

10^-10 m

What is the charge of a proton?

+1.6x10^-19C

What is the charge of an electron? (e)

-1.6 x 10^-19 C

What is the mass of a proton and neutron? (u)

1.67 x 10^-27kg

What is the mass of an electron?

9.11 x 10^-31 kg

What is the value of a unified mass unit?

u

What is an isotope?

A variety of an element with the same number of protons but a different number of neutrons

what physical properties do isotopes have?

Slightly different physical properties to the abundant element

What is the specific charge?

Charge per unit mass

What does specific mean?

per kg

What is the specific charge of an electron?

-1.76 x 10^11 Ckg^-1

What is the specific charge of a proton?

9.58 x 10^7 Ckg^-1

what are the four fundamental forces?

gravitational, electromagnetic, strong nuclear, weak nuclear

when does the maximum attraction of the strong nuclear force occur?

at 1.0 fm

what two things does the snf do?

• provides an attractive force between nucleons with a range of about 3.0 fm

• overcomes the repulsive electrostatic force exerted by positively charge protons on each other

at distances less that 0.5fm is the snf attractive or repulsive?

repulsive

at distances more that 0.5fm is the snf attractive or repulsive?

attractive

at what distance does the snf become insignificant?

3.0 fm

what does the snf work between?

all three combinations of nuclear particles

what does the electrostatic force do?

causes repulsion between protons

at what distance does the ef cause repulsion?

above 0.5fm

at what distance does is the snf larger than the ef? what does this cause the protons to do?

around 1.0fm (so protons attract)

at what distance does is the ef larger than the snf? what does this cause the protons to do?

above 3.0fm (so protons repel)

When does alpha radiation occur?

when the nucleus is very large

when does beta plus decay occur?

When a nucleus has too many protons

When does beta minus decay occur?

When the nucleus has too many neutrons

What is a alpha particle?

a helium nucleus

what does a Beta minus particle consist of?

a fast moving electron

what does a Beta plus particle consist of?

a fast moving positron

what does the neutron decay into after beta minus decay

a proton and electron

other than an electron what other particle is emitted after beta- decay

an antineutrino

how does the proton number change after beta- decay

proton number increases by 1

what does the proton decay into after beta+ decay?

a neutron and W+ boson

other than a positron what else is emitted in beta+ decay?

a neutrino

how does the proton number change after beta+ decay?

proton number decreases by 1

what is gamma radiation?

EM radiation emitted from an unstable nucleus

when does gamma radiation occur? why?

Straight after alpha or beta decay. The child nuclide formed often has excess energy (release as gamma)

properties of neutrinos

• very difficult to detect

• nearly zero mass and no charge

• barely interact with matter

what does beta decay from a particular nuclide produce?

a constant amount of energy

what has to happen because beta particles emerge with a range of kinetic energy?

a neutrino must be emitted with the remaining kinetic energy

what is EM radiation?

radiation emitted by charged particles that are losing energy

what does EM radiation consist of?

two linked electric and magnetic fields that are both at right angles to each other and are in phase

what is the equation for wave speed?

frequency x wavelength

How is EM radiation emitted?

as short bursts of waves, each burst leaving the source in a different direction

what is a photon

a packet of waves

state the the equation linking photon energy and frequency

Photon energy = planck constant x frequency

state the equation linking photon energy, wavelength and wavespeed

photon energy = hc/wavelength

what is the value of planck’s constant

6.63×10^-34

what is the wavelength of a radio wave?

>0.1mm

what is the wavelength of microwave

0.1m - 1mm

what is the wavelength of infrared rays?

1-700mm

what is the wavelength of visible light

700mm - 400nm

what is the wavelength of ultraviolet?

400nm-1nm

what is the wavelength of x-rays

10nm—0.001nm

what is the wavelength of gamma rays

<1nm

what is a hypothesis?

A statement that links the independent and dependent variable

give two examples of a charged particle losing energy

1. a fast-moving electron is stopped or slowed down or changes direction

2. an electron in a shell of an atom moves to a different shell of lower energy

what is the einstein equation?

E = mc²

what is 1 electron volt equal to in joules

1.6 × 10^-19 J

what is an electron volt

the energy required to move an electron through the p.d of one volt

Properties of antimatter

1. same rest mass

2. opposite charge

3 examples of antimatter

antiproton, positron, antineutron

what is annihilation

when a particle and its corresponding antiparticle collide and as a result their masses are converted into energy. This energy as well as the kinetic energy is carried away by photons of equal frequency travelling in different directions in order to conserve momentum

what is pair production

when the rest energy of a photon is higher than the total rest energy of the particle and antiparticle being created. It usually occurs when the photon travels near a heavy nucleus (sudden change in environment)

what is the electromagnetic force?

a repulsive and attractive force that involves an exchange of virtual photons between charged particles

what is the weak nuclear force?

the force responsible for particle decay, it Is only significant in unstable nuclei.

what is the mass of a virtual photon?

zero

what is the charge of a photon?

zero

what is the range of the electromagnetic force?

infinite

what is the range of gravity?

infinite

what is the range of the weak force?

1 am

what is the relative strength of the EM force?

1

what is the relative strength of gravity?

10^-36

what is the relative strength of the snf?

100

what is the relative strength of the weak force?

10^-3

what is the exchange particle for EM?

virtual photons

what is the exchange particle for gravity?

graviton (undiscovered)

what are the exchange particle for the snf?

gluons and pions

what is the exchange particle for the weak force?

w and z bosons

the smaller the mass of the exchange particle the _____ it travels

further

how long does it take for a virtual photon to be exchanged

10^-18 s

how long does it take for a gluon/pion to be exchanged

10^-23 s

how long does it take for a w boson to be exchanged

10^-10s or longer

what is a feymann diagram

a diagram used to illistrate the interactions between sub atomic particles

do the lines on a FD represent the paths of the particles?

no

what are virtual photons exchanged by?

a wave

what interaction is this?

proton pair interaction

what interaction is this?

electron pair interaction

what interaction is this?

beta minus decay

what interaction is this?

beta plus decay

what interaction is this?

electron capture

what interaction is this?

neutron and antineutrino interaction

what is the equation for proton antineutrino interaction with the exchange particle

p + v- → n + e (w+ boson involved)

what is the equation for a proton electron interaction (with exchange particle)

p + e → n + v (w- boson involved)

what is electron capture

when a proton from a very large nucleus attracts an electron from the inner shell into the nucleus

is charge conserved in neutron neutrino interaction?

yes

what is this?

the particle zoo

hadrons interact via…

the strong force

hadrons are made up of…

quarks