Waves and Radiation Flashcards
What is a Wave?
A wave is a term used to describe how energy is transferred from one point to another
What is wavelength?
Wavelength is the length of one full wave
What is the frequency of a wave?
The frequency is the number of waves that pass a point in one second
What is the amplitude of a wave?
The amplitude of a wave is the distance from the rest point to a crest or trough
What is the period of a wave?
The period of a wave is the time it takes to complete one full cycle
What are the two types of waves called?
Transverse and longitudinal
Describe a transverse wave?
In a transverse wave the vibrations occur perpendicular to the direction of the wave.
Describe a longitudinal wave?
In a longitudinal wave the particles vibrate in the same direction as the wave is travelling
What is the speed of all electromagnetic radiations?
3 X 8 10^8m/s
What are the four properties that identify waves?
Reflection, Refraction, Interference and diffraction
When does reflection occur?
Reflection occurs when a wave strikes a barrier and is reflected off that barrier.
When does refraction occur?
Refraction occurs when a wave changes speed as it moves from one medium to another?
When does interference occurs?
Interference occurs when two or more waves combine
Explain diffraction?
When waves pass by a barrier or by an edge or through a gap they spread or bend behind the barrier this is know as diffraction.
What are the parts of the electromagnetic spectrum?
Radio waves, Microwaves, Infrared, Visible light, Ultraviolet, X-rays, Gamma rays
What part of the electromagnetic spectrum has the longest wavelength?
Radio waves
What part of the electromagnetic spectrum has the greatest frequency?
Gamma rays
What is known as the normal?
The normal is an imaginary line drawn perpendicular to the boundary between the two materials
What is known as the angle of incidence?
The angle of incidence is the angle between the incident ray and the normal
what is known as the angle of refraction?
The angle of refraction is the angle between the refracted ray and the normal
What is the definition of refraction in terms of light?
Refraction is that the light changes speed when moving from one medium to another
What are the two main types of lenses called?
Converging and diverging
Describe an atom?
An atom has a nucleus that is composed of neutrons and protons. the electrons orbit the nucleus
What are the 3 types of radiation?
Alpha radiation, Beta Radiation and gamma radiation
Describe an alpha particle?
An alpha particle is a large particle composed of two protons and two neutrons.
Has an overall charge of +2
Describe a Beta particle?
A beta particle is an electron
Has a charge of -1
Describe Gamma radiation?
Gamma radiation is a high energy photon emitted from an excited or energetic atom
no charge and no mass
How can alpha radiation be stopped?
a sheet of paper or being a distance of 20cm away in air
How can beta radiation be stopped?
Thin sheet of aluminium
How can Gamma radiation be stopped?
Lead or concrete ae required
What is background radiation made up of?
Natural and artificial sources
Name four natural sources of radiation and explain?
Cosmic rays - Radiation from space
Animals - Animals emit natural levels of radiation
Rocks - Some give off radioactive radon gas
Soil and plants - Radioactive materials from rocks in the ground absorbed by soil hence passed to plants
What is absorbed dose?
Absorbed dose is the energy absorbed from a radioactive material divided by the mass of the material receiving the dose?
What is Equivalent dose?
Equivalent dose is the absorbed dose multiplied by the radiation weighting factor
What are some of the uses of nuclear radiation?
Diagnosis - X-Ray, Tracers Radiography Tracers Sterilisation Carbon Dating
What is meant by the term half life?
the half life of a radioactive source is the time for the activity to fall to half its original value?
What is meant by the term Activity?
Activity of a radioactive source is the number of nuclei decaying per second
Explain briefly how a nuclear power stations work?
Radioactive materials used to generate large amounts of heat
This heat is used to turn water into steam
Steam drives turbines to generate electrical energy
What are the two main types of nuclear reactions?
Fission and fusion
What is fission?
Fission is the process in which one nucleus splits into more than one nuclei which releases energy
What is fusion
Fusion is the combing of nuclei of light elements to give heavier nuclei.
