P13 EM waves Flashcards
name the parts of the EM spectrum in order, starting with the longest wavelength one
- radio
- microwave
- infrared
- visible light
- ultraviolet
- X-rays
- gamma
name the parts of the EM spectrum in order, starting with the shortest wavelength one
- gamma
- X-ray
- ultraviolet
- visible light
- infrared
- microwave
- radio
how fast do EM waves travel?
3 x 10to the power of8 m/s
what is the wave equation?
v = fλ
what are electromagnetic waves?
electric and magnetic disturbances that transfer energy (not matter)
which wave on the EM spectrum has the longest wavelength?
radio
which wave on the EM spectrum has the shortest wavelength?
gamma
which wave on the EM spectrum has the lowest frequency?
radio
which wave on the EM spectrum has the highest frequency?
gamma
uses of visible light (4)
- torches
- cameras
- endoscopes
- optical fibres
uses of infrared (4)
- optical fibres
- remotes controls
- thermal imaging
- ovens
uses of microwaves (3)
- microwave oven
- mobile phones
- satellite communications
uses of radio waves (4)
- radio
- bluetooth
- remote control car
- radar
2 dangers of infrared
- skin burns
- damage to eyesight
1 danger of microwaves
heating internal body parts
1 danger of radio waves
heating internal body parts
1 danger of visible light
damage to eyesight
how can x-rays detect internal cracks in metal objects?
- the more dense a substance is, the more X-rays it absorbs from an X-ray beam passing through it
- so an X-ray image will show any cracks or areas where the X-rays have passed straight through, and shadows of where it has been absorbed.
define amplitude
the maximum displacement of a point on the wave from its undisturbed position
the bigger the amplitude the _____ energy the waves carry
more
define wavelength
the distance from a point on a wave to the equivalent point on the adjacent wave
define frequency
the number of waves passing a fixed point per second
how do you calculate the time period of a wave?
T = 1/f
what is wave speed?
the distance travelled by each wave per second
(v = fλ)
what causes X-rays?
X-rays are produced when electrons or pther particles moving at high speeds are stopped
(X-ray tubes are used to produce X-rays)
what causes gamma rays?
gamma rays are caused by radioactive substances when unstable nuclei releas energy
1 difference between X-rays and gamma rays
gamma rays can penetrate substances more than X-rays can because gamma rays have shorter wavelengths.
3 similarities between X-rays and gamma rays
- both travel straight into substances and can pass through them is the substances are not too dense or too thick
- both at the short-wavelength end of the EM spectrum
- carry much more energy/second than longer wavelength EM waves.
explain why a film badge used for monitoring radiation needs to have a plastic case rather than a metal case
- the gamma rays need to be able to pass through the case to get to the film
- gamma rays will not pass through a substance if it is too dense or too thick, so they may not pass through a metal case
- therefore film badge would be ineffective for the user.
waves can tranfer _ and _ ?
- energy
- information
carrier waves are waves that _ information. they do this by varying their _ ?
- carry
- amplitude
what waves can be carrier waves? (4)
- radio
- microwaves
- infrared radiation
- visible light
