intro to module

Question 1

what is an atom.
can it be divided and how many parts?

Answer 1

Smallest unit of matter that has the characteristic properties of a chemical element

Smallest unit into which matter can be divided without the release of electrically charged particles;
Electrons
Protons
Neutrons

Question 2

what is an element

how many atoms is the element made up of

how many elements

Answer 2

Distinct kind of matter which cannot be broken down into two or more smaller kinds of matter

Always made up of the same atom

118 elements have been identified (organised in the Periodic Table)

Question 3

what is the atomic structure

Answer 3

Electrons : negatively charged particles orbiting the nucleus of an atom. The charge on a single electron is -1.6 x 10 -19 Coulomb.

Protons: positively charged particle. The charge on a single proton is +1.6 x 10 -19 Coulomb.

Neutron : neutral particle with no charge.

Number electrons = number of protons so atom has no charge overall
Mass of atom is entirely in the nucleus

Question 4

what is the electron configuration

Answer 4

Negatively charged particles orbiting the nucleus of an atom\

nucleus - proton n neutron
1st shell - 2 electrons
2nd shell - 8 electrons

Question 5

electron configuration
gaining energy and losing energy

Answer 5

Electrons can gain energy and move one shell up (away from the nucleus)

Electrons can emit energy and move one shell down (closer to the nucleus)

Question 6

what is a nuclear force
What’s holding the nucleons

Answer 6

What’s holding the nucleons (collective term for protons and neutrons) in the nucleus?

Laws of electromagnetic force state that like charges repel and opposite charges attract

Protons are positively charged, so why don’t they repel each other?

Question 7

subatomic particles - composite particles

Answer 7

Composite Particles:
Can be broken down further as are made of two or more elementary particles (e.g. protons and neutrons)

Question 8

subatomic particles - Elementary Particles:

Answer 8

Elementary Particles:
Smallest particles not made of any other particles (e.g. quarks)

Question 9

Protons and Neutrons quarks how many up and down quarks do they have

Answer 9

Protons: 2 Up quarks and 1 Down quark

Neutrons: 1 Up quark and 2 Down quarks

Up quarks have a 2/3 positive charge
Down quarks have a 1/3 negative charge

Protons:
U+ U + D
(2/3) + (2/3) + (-1/3) = 3/3 = +1 positive charge

Neutrons:
D+ D + U
(-1/3) + (-1/3) + (2/3) = 0/3 = 0 charge (neutral)

The quarks within each proton and neutron are held together by elementary particles called Gluons which providing the binding force

Question 10

nuclear force - mesons

Answer 10

Mesons:
Part of the Hadron particle family (particles composed of two or more quarks)
Composed of a quark and an antiquark

When the nucleons (protons and neutrons) are close together in the nucleus, meson particles are exchanged between them
This creates a strong nuclear force which pulls the nucleons together
Mesons are used to explain the properties and interactions of quarks

Question 11

Atomic Stability large atoms nucleus vs small atoms nucleus

Answer 11

The strong binding force by mesons is mostly effective up to a nucleus size of 10−15m

Atoms with a large nucleus (large number protons and neutrons) are less stable

As the mass increases, the strong nuclear force cannot hold all the nucleons in the nucleus

Question 12

atomic vs mass number

Answer 12

atomic - the number of protons in the nucleus of an atom

mass number - total number of protons and neutrons present in the nucleus of an atom is called the mass number.

Question 13

Element Stability

Answer 13

Elements having an atomic number greater than 83 than to be unstable

Example: Uranium
Due to the large number of protons and neutrons, there is disintegration of the atomic structure and material becomes radioactive

Question 14

nuclear force weak vs strong

Answer 14

Strong Nuclear Force
Holds the nucleus together

Weak Nuclear Force
Responsible for radioactive decay

Stability of an atom depends on the nuclear binding energy and strong nuclear force

Nuclear binding energy is the energy required to break the nucleus into its constituent particles

Question 15

isotopes

Answer 15

Every element in the periodic table has multiple variations

These variations have the same atomic number (protons) but different mass numbers

The atomic number (protons) provides the chemical identity of the element

Some isotopes are stable, some are unstable

Question 16

Radioisotopes

Answer 16

Not all isotopes are radioactive

Some isotopes are stable, some are radioactive

Unstable, radioactive isotopes are called radioisotopes/radioactive isotope

Unstable isotopes emit particles and energy and transform into a different element (different chemical properties/identity)

This transformational change is called radioactive decay

Question 17

what is Electromagnetic Force
what is an Electric fields:
what is Magnetic fields:

Answer 17

Physical interaction that occurs between electrically charged particles
Originates from electric and magnetic fields

Electric fields:
Produced by an electric charge (electrons)
Exerts force on all other charges in the field, either attracting or repelling them (e.g. the attractive force holding the atomic nucleus and electrons together in atoms)

Magnetic fields:
The space near a magnet or an electric current where a physical field is created from a moving electric charge that creates force on other moving electric charges

Question 18

what is an Electromagnetic Waves

Answer 18

An accelerating charged particle produces an electromagnetic (EM) wave
EM waves are electric and magnetic fields traveling through empty space at the speed of light
They transport energy through space
This energy can be delivered to charged particles a large distance away from the source

Accelerating charges produce changing electric and magnetic fields
Changing electric fields produce magnetic fields and changing magnetic fields produce electric fields
This interplay between induced electric and magnetic fields leads to propagating electromagnetic waves through free space

Question 19

what is Electromagnetic Radiation

Answer 19

Waves radiating from electrically charged particles

Charged particles are referred to as photons are propagating (radiating) through space, carrying electromagnetic radiant energy

Question 20

what is Electromagnetic Radiation what characteristics does it have

Answer 20

Characteristics:

Strength varies in an alternating or cyclic fashion

Distance between two consecutive +ve peaks = wavelength (λ)

Number of cycles that pass a fixed point per second = frequency (ν)

Velocity = distance travelled forward per second => λ x ν

All EM waves travel at the same velocity in a given medium (speed of light in a vacuum)

Question 21

Electromagnetic Spectrum
long vs short wavelengths

Answer 21

The range of frequencies (spectrum) of electromagnetic radiation and their respective wavelengths and photon energies

Long wavelength = low frequency

Short wavelength = high frequency

Question 22

Electrical Circuit

Answer 22

A path for transmitting an electric current

The circuit must have a:
Device that gives energy to the charged particles constituting the current, such as a battery or a generator

Devices that use current, such as lamps, electric motors, or computers
The connecting wires or transmission lines

The laws that govern how electric circuits behave are Ohm’s Law and Kirchhoff’s rules

Question 23

Alternating Current vs Direct Current

Answer 23

Alternating Current
A type of electrical current in which the direction of the flow of electrons switches back and forth at regular intervals or cycles
Type of current used in residences and business
From a power plant, generator, alternator etc.

Direct Current
An a electrical current which flows consistently in one direction, from positive to negative terminals
From batteries, fuel cell, solar panel, dynamo etc.

Question 24

Alternating Current

Answer 24

A simple AC generator consists of a coil of wire rotating in a magnetic field

As one side of the coil moves up through the magnetic field, a potential difference is induced (created) in one direction

As the rotation continues and that side of the coil moves down, the induced potential difference reverses direction

Electrons in the (copper) wire move towards the positive side of the magnet when this in close proximity or away from the negative side when this is in close proximity

Question 25

Direct Current

Answer 25

Unidirectional flow of current; current only flows in one direction

Voltage and current can vary over time as long as the direction of flow does not change

Different sources but batteries most common

Question 26

Electrical Current

Answer 26

Flow of charged particles
Results from the flow or movement of electrons

Unit of current = Ampere (Amps) [A]
1 Amp = current which flows when an electric charge of one coulomb passes a given point in one second [Coulomb = measure of electric charge]

For diagnostic radiography exposures = milli Amps (mA)

Question 27

Voltage

Answer 27

The electrical force between two points that would drive an electric current between these points
The pressure from an electrical circuit’s power source that pushes charged electrons (current) through a conducting loop
The difference in electric potential between two points (potential difference)

Unit of voltage = Volt (V)
1 Volt = energy consumption of 1 joule per electric charge of 1 coloumb [Joule = measure of energy]

For diagnostic radiography exposures = kilo volts (kV)
For therapeutic radiography exposures = mega volts (mV)