2.1 Waves Flashcards
Define wave
the propagation of energy thru a medium or vacuum without any transfer of the medium itself
Define a progressive wave
A wave that transports energy by causing vibrations in the material or medium thru which it moves
Define a mechanical wave
Requires a substance (medium) thru which to travel
2 egs mechanical wave
Sound or water
Progressive waves are either —— or ———
Transverse or longitudinal
Define transverse wave
Waves in which the vibration of the medium is perpendicular to the direction of propagation of the wave
Define a longitudinal wave
The vibrations are parallel to the direction of propagation of the wave
Two egs of a longitudinal wave
Sound and ultrasound
Define periodic time T
The time taken for a wave to make one complete vibrational cycle (time taken to repeat itself)
Define amplitude
The maximum displacement of a particle of a medium from its equilibrium position
Define frequency
The number of complete waves to pass a fixed point per second
Define wavelength
The distance the wave form progresses in periodic time T
What is meant by “in phase”?
Corresponding points on each wave coincide in time
Define electromagnetic wave
A transverse wave which has both an electric and a magnetic oscillating component in planes perpendicular to each other
Define unpolarised light
A light wave which is vibrating in more than one plane
Define Polarized light
the vibrations of the wave are confined to a single plane
Define polarization
The process of transforming unpolarised light into polarized light
What is a Polaroid filter?
Polaroid filters can polarize light because of the chemical composition of the filter material
Wavelength of a gamma ray
Smaller than 10^-11
Wavelength of X-rays
10^-10
Wavelength of ultra violet light
10^-8
Wavelength of visible light
(4-7)x10^-7
Infra red wavelength
10^-4
Microwaves wavelength
10^-2
