Waves Flashcards
(23 cards)
Can transverse waves travel in a vacuum?
Yes (EM waves)
Can longitudinal waves travel in a vacuum?
No
What is a longitudinal waves?
In Longitudinal waves, particles oscillate parallel to the direction of energy transfer
What is a TRANSVERSE wave?
In transverse waves, particles oscillate perpendicular to the direction of energy transfer
Define FREQUENCY:
The number of waves that pass a fixed point per unit time
Define WAVEFRONT
An imaginary surface that represents points of a wave that are at the same point in their cycle
Define
DEFINE the DOPPLER EFFECT
The apparent change in observed wavelength and frequency of a wave emitted by a moving source relative to the observer
USES of RADIO WAVES
-communication + broadcasting
USES of MICROWAVES
-cooking
-satellite transmissions
USES of INFRARED RADIATION
-heating
-night vision equipment
USES of VISIBLE LIGHT
-optical fibres
-photography
USES of UV LIGHT
-fluorescent lamps
USES of X-RAYS
-observing the internal structure of food and objects
(X-rays are absorbed by denser parts of the body such as bones)
USES of GAMMA RAYS
-sterilising food and medical equipment
RISKS of MICROWAVES
-can cause heating to internal organs
RISKS of INFRARED
-can cause skin burns
RISKS of UV light
-can cause sun burn and blindness
RISKS of GAMMA RAYS + X-RAYS
-can cause mutations
REFRACTION rules
SLOWS towards
SPEEDS away
How do optical fibres work?
In optical fibres, the light travelling down the fibre is totally internally reflected each time it hits the edge of the fibre.
DOPPLER EFFECT higher:
-wavefront COMPRESSED, moving in this direction
-shorter wavelength
-higher frequency
-person A seems to hear a higher pitch
DOPPLER EFFECT lower:
-wavefronts will be stretched out
-longer wavelength
-lower frequency
-pitch seems to have decreased
