Discovery, Properties & Production of X-rays Flashcards
Who discovered x-rays and when ?
The German scientist Wilhelm Conrad Roentgen on November 8, 1895
What tube was the first to be experimented with, and how did it work ?
The Crookes tube - William Conrad Roentgen discovered that there was a glow on a sheet of barium platinocyanide-coated paper far away from the tube. So he named the mysterious energy ray/ photon x-ray ‘x’ meaning unknown
What is the wave-particle duality ?
The concept by which light/x-ray can behave both as a wave and a particle (photon- particle of light).
Wave properties:
- has oscillating electric and magnetic fields at right angles to each other (electromagnetic waves)
- has an amplitude, wavelength and frequency as a wave - wavelength and frequency varies dependent on colour of light
- can defract as a wave
- have negative and positive interference
Particle properties:
- can exhibit photoelectric effect (
Blue light has high enough frequency to eject an electron off certain metals, whilst red light does not) - travel in straight lines
- electrons behave same way but are charged whilst a photon is neutral
Why can x-rays be described as waves ?
They move in waves that have wavelength (f) and frequency (λ)
What is the symbol for speed of light ?
c = speed of light
What is the equation for speed of light ?
c = f λ
What is the definition of wavelength ?
The distance between 2 successive troughs or crests of a wave
What unit is wavelength measured in ?
Angstroms (Å) (1 Å = 10^ -10 m)
What amount of angstroms does x-rays used in radiography range between ?
0.1 to 1.0 Å
What is the definition of frequency?
The number of waves passing a given point per given unit of time (second)
What are the symbols for wavelength and frequency ?
Frequency : f
or the Greek letter v, pronounced ‘nu’
Wavelength : λ
What units is frequency measured in ?
Hertz (Hz) - (l/s)
What amount of Hertz does x-rays used in radiography range between ?
3x10^18 and 3x10^19 Hz
What describes the relationship between wavelength and frequency?
An inversely proportional relationship
What is the relationship between wavelength and frequency for higher energy-rays?
Decreased wavelength and increased frequency
What is the relationship between wavelength and frequency for lower energy-rays?
Increased wavelength and decreased frequency
What does the symbol E stand for?
E = Photon Energy (1.986 x 10 ^ -25)/ λ
What does the symbol h stand for?
Planks constant (6.62 x 10^ -34 Js)
What are three formulas for E ?
E = hv
E = hc/λ
E = (1.986 x 10^ - 34 Js)
What property of X-rays make it impossible for them to be felt, smelled or heard?
Invisibility
X-rays being electrically neutral make what impossible?
X-rays having neither a positive or negative charge make it impossible for them to be accelerated or made to change direction using a magnet or electrical field
Why do x-rays produce no resistance in being put into motion nor do they produce force?
Because they have no mass
What speed do x-rays travel at?
The speed of light in a vacuum ( 3 x 10^8 m/s) or (186,000 miles per second)
How do x-rays travel?
In a straight line
How can x-rays interact with matter?
They can be absorbed or scattered