waves Flashcards
Transverse Waves
A type of wave in which the particles oscillate at right angles to the direction the wave travels
Longitudinal Wave
A type of wave in which the particles oscillate parallel to the wave direction
wavelength / lambda
the distance between two matching points on neighbouring waves. in metres
amplitude
the maximum displacement a point moves from the centre of oscillation. in metres
amplitude in comparison to energy
the larger the amplitude, the greater the energy of the wave
Period
the time taken for a point on a wave to move through one complete oscillations. in seconds
Frequency
any wave is the number of oscillations per second measured in hertz
frequency equation
f = 1 / T
Mechanical waves
required a medium for transmission and are generated by vibrating sources
electromagnetic waves
are created when charged particles are accelerated. They require no medium for transmission
Maxwells conclusion
- maxwell found that the speed of the em waves would travel at a speed c = 1/ eu
- light must be an em wave as its same as his answer
- maxwell predicted that waves must also exist with frequencies much bigger and much smaller than light in a continuous spectrum
what did hertz demonstrate + discover
demonstrated - reflected, refracted and polarised
discovered - radio waves
Experiments with radio waves
- by placing a sheet of metal between the transmitter and detector he showed that radio waves are reflected by metal
he discovered that insulators do not absorb radio waves by placing his detector in another room
he strengthened his beam by placing a concave reflector around it
x-rays
had a wavelength of the order 10^-10
electrons emit x rays after high speed collisions or through a high energy transition in an atom
in space, x rays come from very hot stars of from charged particles accelerated to enormous speeds
x rays are produced by making high speed electrons collide with a metal target
EM Waves properties
1) travels at the speed of light
2)can be reflected, refracted and polarised
3)Show interference and diffraction effects
4) can travel through a vacuum
- Different frequencies interact with matter in very different ways
What is interference in physics?
Interference occurs when two or more waves meet and their amplitudes combine either constructively or destructively, resulting in changes in the overall wave pattern.
what is constructive interference?
when two waves are in phase and the amplitude increase when interfere
Destructive intefarance
180 degrees out of phase therefore trough is inligned with peak causing there to be no amplitude
What conditions are necessary for constructive interference?
Constructive interference occurs when waves meet in phase, meaning their peaks and troughs align, and their path differences are whole multiples of the wavelength.
What conditions are necessary for destructive interference?
Destructive interference occurs when waves meet out of phase, meaning their peaks align with troughs, and their path differences are odd multiples of half the wavelength.
What is phase difference?
Phase difference is a measure of how “in step” or out of step two waves are with each other. It’s usually measured in degrees or radians
How is phase difference represented mathematically?
Phase difference (ϕ) can be calculated using the formula: ϕ = (2π / λ) × path difference, where λ is the wavelength of the wave.
the principle of superposition
Where two or more waves meet, the total displacement at any point is the sum of the displacements that each individual wave would cause at that point
refraction definition
when light travels from one transparent material to another it changes direction . This happens because the light changes velocity
