Flashcards
astrophysics
Flashcards do conjunto (68)
- 1Transverse waves transfer energyPerpendicular to direction of vibration
- 2Longitudinal waves transfer energyParallel to direction of vibration
- 3An example of transverselight
- 4example of longitudinalsound
- 5amplitude- Amaximum displacement from point of equilibrium
- 6wavelength-/\distance between two identical points on wave cycle
- 7frequency- fnumber of vibrations per unit time
- 8time period - Ttime taken for one complete vibration
- 9law of reflectionangle of incidence = angle of reflection
- 10Law of refractionrefractive index is ration of speed of light in a vacuum to speed of light in the new material
- 11seismic waves are measured usingseismometres
- 12P waveslongitudinal
- 13S wavestransverse
- 14P waves arrive1st
- 15S waves arrive2nd
- 16epicentre of earthquake can be found using3 seismometers. Find the time difference in arrival between P and S waves.
- 17S waves cannot pass throughliquid outer core so they reflect back
- 18P waves refract a lot at boundaries whendensity changes drastically
- 19all electromagnetic waves aretransverse
- 20convex lensfocuses light to a point
- 21concave lensspreads out light. diverging
- 22convex mirrordiverges light
- 23concave mirrorfocuses light. converging
- 24refracting telescopelight is refracted by convex lens. convex lens converges light . Light is then refracted by eyepiece lens inverting the image
- 25reflecting telescopelight reflects off the primary mirror which is concave so it converges light onto the secondary mirror which is plane. this mirror stops the observer obscuring part of the image. Light is refracted by the eyepiece lens, magnifying image.
- 26modern telescopes for astronomy arereflecting telescopes as they are cheaper and the mirrors reflect all wavelengths of light.
- 27continuous spectrawhite light disperses producing a spectrum of coloured light. contains all wavelengths in the range.
- 28emission spectrawhite light from a hot gas disperses. Black background with few coloured lines- emitted wavelengths of elements in the hot gas.
- 29absorption spectrawhite light passes through a cool gas. colourful spectrum with dark lines-wavelengths absorbed by atoms in the gas.
- 30each element has unique lines on spectra in order toidentify elements in stars.
- 31in hot environment of stars atoms in the gas getexcited.
- 32when the atoms in a gas get excitedthey increase in energy level.
- 33when the excited atoms drop back they willemit a specific light which produces lines on the emission spectra.
- 34pitchfrequency
- 35loudnessamplitude
- 36short wavelengthhigh frequency
- 37echoesreflections of sound
- 38blueshort /\
- 39redlong/\
- 40moving towards observerhigh pitch, short wavelength,blueshift
- 41moving away from observerlow pitch,long wavelength,redshift
- 42binary starstwo stars orbiting centre of mass
- 43towards earthblueshift
- 44away from earthredshift
- 45speed of recessionspeed at which star moves away from observer
- 46Hubble's constant70kms^-1Mpc^-1
- 471 km1000 m
- 481 ly9.5x10^15 m
- 491 Mpc3.1x10^22 m
- 50d=v/H0d-Mpc
v-km/s - 51age of universe1) gradient on graph=70kms^-1Mpc^-1
2)km/s/Mpc=70x1000=70000 ms^-1Mpc^-1,70000/3.1x10^22= H0 in s^-1
3)t=1/H0 so fint time in s then convert to years by /(365.25x24x60x60) - 52redshiftstars moving away
the bigger the redshift, the faster stars are moving away. - 53change in /\//\=change in f/f=v/cc=speed of light
v=speed of recession
f=frequency
/\=wavelength - 54e=hfe-joules
h-6.626x10^-34
f-hertz - 55m=fl obj/fl eyem-X
- 56power of lens=1/fl of lensp-dioptres
fl-metres - 57ni sini=nr sinrn-refractive index
sin-angle - 58gradient=change in y/change in x
- 59n=c/Vn=refractive index
c=speed of light in vacuum
V=speed of light in material - 60V=f/\V=wave speed
f=frequency (Hz)
/\=wavelength - 61f=1/TT=s
- 62radio waves/\=10^3-10^-3 m
f=10^5-10^11 Hz - 63microwaves/\=10^-1-10^-3m
f=10^9-10^11 Hz - 64infrared/\=10^-3-10^-5
f=10^12-10^14 Hz - 65visible light/\=10^-5-10^-7
f=10^13-10^15 - 66uv/\=10^-7-10^-8
f=10^15-10^16 - 67Xray/\=10^-9-10^-11
f=10^17-10^19 - 68gamma ray/\=10^-12
f=10^20-10^21
Informações
- Descrição
- Year 7 Physics FlashCards sobre astrophysics, criado por Lakshmi Lakshmanan em 03-05-2019.
- Criado por
- Lakshmi Lakshmanan
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