Dangers and uses Flashcards
What does the amount of energy transferred by a wave depend on?
the wavelength or frequency
the highest frequencies are the most energetic and the most dangerous waves
Uses of gamma rays and why
- to sterilise food and medical equipment
- in scanners to detect cancer
- to treat cancer
gamma rays kill cells and living organisms like bacteria, so they remove them from food/equipment
radiation markers attach to cancer cells in a body and can be scanned to determine the location of the cancer
cancer cells can be killed by targetted radiation
Uses of x-rays and why
- to look inside objects, including medical x-rays
- in airport security scanners, to see what people have in their luggage
x-rays pass through most material, but are absorbed by bone and metal
this causes them to show up on an x-ray, letting them be seen clearly
uses of ultraviolet and why
- to detect security marks made by using special pens
- inside fluorescent lamps
- to detect forged banknotes (real banknotes have markings that glow in UV light)
- to disinfect water
some UV light is visible to humans
when shined on specific materials and reflect off them, allowing them to be seen
this can be used to prove the authenticity of something
UV radiation heats up water, killing microorganisms in it
uses of visible light and dangers
- allows us to see, lights up rooms and streets etc.
- photography
it could damage your eyes if it is too bright
uses of infared and why
- cooking
- thermal imaging
- short range communication
- remote controls
- optical fibres
- security systems
it heats objects by increasing the internal energy of the particles
all objects emit infared radiation, so it can be picked up by a camera
it can transfer data over a short distance, or a longer one using fibre optic cables
it can detect movement by detecting increased radiation levels
uses of microwaves and why
- mobile phones
- satellite transmissions
- cooking
increases internal energy of the bonds holding particles together
travels easily through the atmosphere
uses of radio waves and why
- broadcasting radio and TV programmes
- communicating with ships, aeroplanes and satellites
longer wavelength means it easily travels through air, and is harmless to humans
dangers of gamma rays and x-rays
are ionising radiation
can cause mutations in DNA of cells
this could kill the cells or cause cancer
dangers of ultraviolet rays
can damage skill cells, causing sunburn
over time, exposure to UV can cause skin cancer
it can also damage the eyes and cause problems
dangers of infared
transfers thermal energy, so too much can cause skin burns
dangers of microwaves and radiowaves
microwaves heat water, so they can heat the water inside our bodies
heating cells can damage or kill them
radiowaves aren’t absorbed by humans, so are mostly harmless
State which type(s) of EM radiation are:
a) used for communicating [4]
b) used for cooking [2]
c) used for cleaning things [2]
d) most dangerous [3]
a) radio waves, microwaves, infared and visible light
b) microwave and infared
c) ultraviolet and gamma
d) ultraviolet, x-rays, and gamma
Explain how x-rays are useful to doctors but can also be harmful to patients [3]
x-rays are userful because they allow them to detect broken bones but can damage cells, which could cause mutations or cancer
Explain how gamma rays can be used to detect cancer even though they can also cause it [2]
gamma rays could pass through the body and be detected by, e.g. a gamma camera, allowing a doctor to see if cancer is present
gamma rays may cause cancer, but this is a risk worth taking is there is a possibility that the patient has malignant cancer that may lead to death
