P6 Flashcards
What are the 2 types of waves?
Transverse and longitudinal
What are transverse waves?
When the oscillations are perpendicular (at a right angle) to the direction of energy transfer.
What are longitudinal waves?
When the oscillations are parallel to the direction of energy transfer
What do all longitudinal waves require in order to travel?
A medium
Do all transverse waves require a medium to travel in?
No
What do all waves transfer from one place to another?
Energy
In a sound wave what is the name of the area/region where air particles are close together?
Compressions
In a sound wave what is the name of the area/region where air particles are spread out?
Rarefactions
What 3 things happen to waves?
They are either absorbed, transmitted or reflected.
What do transmissions sometimes lead to?
Refraction → a change of direction
What are the 7 types of electromagnetic waves. (In order of highest frequency
Gamma, X-ray, ultraviolet (UV), visible, infrared, microwave, radio waves
What are similarities of EM waves?
- transverse
- travel at the same speed through air or a vacuum
- they are vibrations of electric and magnetic fields
what are differences of EM waves
- travel at different speeds in different materials
- vary in wavelength
why is there such a large range of frequencies in EM waves?
because EM waves are generated by a variety of changes in atoms and their nuclei
which EM wave has the highest / least frequency?
Gamma waves = highest
Radio = lowest
which EM wave has the highest / least wavelength?
radio waves = highest
gamma waves = lowest
where do EM waves transfer energy from and to?
from the source of the wave to an absorber of the wave
What are gamma waves used for?
- medical imaging and therapy
- sterilisation
- food preservation
- destroying bacteria and tumours
- astronomy
what are the risks of gamma waves?
are extremely penetrating and damaging to living tissues
X- rays
X- rays pass easily through the flesh but no so easily through denser materials like bones or metals.
- its the amount of radiation absorbed ( or mot absorbed) that give you an X-ray image
what X- rays used for? (3)
- medical and industrial imaging
- treating cancer
- detecting weapons
how are Gamma and X-rays used to treat cancer?
high doses of these rays kill all living cells - so they are carefully directed towards cancer cells, to avoid kill to many normal/ healthy cells