Waves Flashcards
What differentiates electromagnetic waves?
wavelength and frequency
inversely realted- one goes up other goes down
Name the elctromagnetic waves in order
radiowaves, micro waves, infared,visibile light, ultra violet, x rays, gamma rays
as you go to the right- wave length decreases
as you go to the right frequency increases.
What electromagnectic wave can humans detect?
visible light- all colours
How are gamma rays emitted?
byy radioactivity
How is visible light, ultra violet and x rays emitted?
by electrons dropping energy levels
How is infared emitted?
bu bonds holding molecules together vibrate.
What happens to waves after being emitted?
they can be transmitted, reflected or absorbed.
What is a amplitude?
maximum displacement of a point on a wave from it’s undisturbed posiiton.
What is a wavelength?
distance from a point on one wave to the equivalent point on the adjacent wave.
What is frequency?
number of waves passing a point each second
What is frequency measured in?
hertz Hz
1Hz= 1 wave per second.
What is the period?
amount of time in seconds for a wave to pass a point
How are waves produced?
changes take place in the atom or nuclei of an atom when waves are generated or absorbed.
Which waves are hazardous to the human body?
gamma rays, ultra violet, xrays
What can ultraviolet waves cause?
skin to premature early and skin cancer
What waves are ionising radiation?
x rays and gamma rays
What do x rays and gamma rays cause?
skin cancer and mutation of genes
How can radio waves be produced?
when electrons oscillate in electric currents.
What are the uses of radiowaves?
used to transmit radios and terrestial tv signals.
Why are radio waves used?
can travel long distances without being absorbed.
spread out between hills
What are microwaves used for?
to heat up food.
Why are microwaves used ?
energy causes temperature of food to increase
used to communicate with satellites in space as they don’t reflect or refract in earth’s atmosphere.
What are the uses o infared?
used for heater and cook food in oven.
Why is infared used?
energy of infared easily absorbed by surface of objects.
infared cameras to check for heat loss in buildings.
What are the uses of visbile light?
communication using fibre optics.
optical fibres used to carry telephone and cable tv signals.
short wave length carry great amount of imformation.
What are the uses of ultraviolet?
used for lightbulbs.
sun tanning
Why is ultra violet used?
shortwave length carries more energy than visible light.
How is ultraviolet converted to visible light?
energy of ultraviolet absorbed by internal surface of bulb and converted into visible light. (requires less energy)
What are x rays and gamma rays used for?
medical imaging.
Why are x rays and gamma rays used ?
x rays can detect broken bones
gamma rays can detect cancers.
Are gamma rays and x rays prenetative?
yes- easily pass through body tissue.
x rays are absorbed by bones.
Can gamma rays and x rays be used for medical tretaments?
to treat cancer.
