waves Flashcards
what is amplitude
maximum displacement from rest position. larger the amplitude the more energy a wave carries
what is wavelength
distance between two equivalent points on adjacent waves
what is frequency
number of waves passing a point each second
what is period
the time needed for once complete cycle of vibration to pass a given point
what is the correlation between frequency and period
as the frequency of a wave increases the period of a wave decreases
equation for period
period t (seconds) = 1 divided by frequency (Hz)
wave speed equation
wave speed = frequency x wavelength
what are electromagnetic waves
electromagnetic waves are transverse waves that transfer energy from the source of the waves to an absorber
properties of electromagnetic waves
reflect refract diffract absorb transmit
how do electromagnetic waves differ from other waves
because they can travel through a vacuum
they form a continuous spectrum and all types of electromagnetic wave travel at the same velocity through a vacuum
what are waves in electromagnetic spectrum grouped in
grouped in terms of frequency and wavelength
from long to short wavelength or low to high frequency the order of electromagnetic spectrum is
radio waves microwaves infrared visible light ultraviolet xrays gamma rays
radio waves in communication long and short
transfer energy: short radio wave (10m-100m) can be sent over long distances but have to be reflected of the earths atmosphere (ionosphere)
long radio waves (1-10km) waves can diffract (bend) around earths surface
how are radio waves produced
radio waves are made by oscillating electric and magnetic fields
AC current creates the oscillating electric and magnetic fields which creates radio waves in a transmitter
receiver absorbs radio waves and the energy is transferred to the elections in material of receiver
the energy absorbed causes the electrons to oscillate and generates an alternating current
microwaves used by satellites
microwaves are used as they can pass through the earths watery atmosphere
transmitter sends information into space to a satellite
the satellite transmits signal back to earth in a different direction
received by a satellite dish
time delay between signal being sent and received