further physics Flashcards
what are advantages of controlling a telescope from a computer?
- can directly record + process data collected
-
what are the advantages of the joint venture of international co-operation?
- expertise can be shared
- cost of building telescopes is shared
- astronomers can book time on telescopes in diff countries allowing them to see stars on other side of earth
eg gemini observatory in chile shared between Australia + 6 others
the great canary telescope which allows astronomers to capture distant lights in the universe, can be accessed how?
- directly at the site
- through remote computer control
- through internet
what are advantages of space telescopes?
- avoid absorption + refraction effects of atmosphere
- use parts of electromagnetic spectrum that atmosphere absorbs
what are the disadvantages of space telescopes?
- expensive
- uncertainties associated with space programmes eg launch delays
what are the 2 major
w
why has Hawaii been proven to be an ideal location?
- high altitude
- isolated location (less poll to interfere with received signal)
- frequent cloudless skies
- equatorial location (best view of solar eclipse)
what factors should be considered when planning, building or closing an observatory?
- cost
- environmental impact
- working conditions for employees
what can light, water and sound waves all be?
- refracted
- diffracted
what is refraction?
when waves cross boundary between 1 medium and another, freq is same but change in wavelength leading to change in wave speed causing wave to change direction
what is diffraction?
when waves move through narrow gap or past obstacle, they spread out from edges
most obvs when:
- size of gap is similar to or than wavelength of wave
- waves that pass obstacles have long wavelength
w
w
what is the refraction of white light?
colour that make up white light refracted by diff amounts as they pass through prism:
- red most
- violet least
occurs bc colours that make up white light have diff frequencies and wavelengths
what is the lunar cycle?
describes moons appearance during 28 day obit. moons shape due to part of moon that’s visible to earth
able to see moon bc suns light reflected from it
during the moons orbit around the earth, what are the different faces of the moon?
- dark face (new moon)
- light face (full moon)
- all points in between new moon and full moon
explain the earth and the moon?
while earth rotating on axis, moon orbiting earth in same direction
due to this orbiting movement, moon appear to travel east-west across sky over 24 hours
what is a solar eclipse?
when moon passes between earth and sun. happens during new moon and results in moon casting shadow on earth
what is a total solar eclipse?
when moon directly in front of sun obscures earths view of the sun
observing directly can damage eye.
what is a lunar eclipse?
when earth is between sun and moon resulting in earth casting shadow on moon
what are extrasolar planets?
planets that orbit star other than sun
what is the evidence for the expansion of the universe?
spectra observed from elements in stars belonging to distant galaxies indicate light is red shifted. more distant a galaxy, more light is red shifted
motion of galaxies show space is expanding
explain pressure and volume?
gas pressure caused by particles moving. when particle collides with object, exerts pressure
pressure depends on:
- # of collisions per sec
- momentum of particles
as vol of gas reduced, particles have less room to move so collide with each other more often increasing pressure:
(pressure x volume = constant)
explain pressure and temperature?
if gas heated up, particles move faster increasing momentum and force they exert when collide
explain absolute zero?
as temp of gas reduced, particles move flow and pressure falls
particles stop moving and have no energy to lose + temp cant go lower, occurs at -273 - absolute zero
what is absolute temperature?
measure of temp starting at absolute zero
to convert from..
- kelvin to degrees, - 273
- degrees to kelvin, + 273
what 3 parts does a star have?
- core hottest part where nuclear fusion takes place
- convective zone where energy in form of photons is transferred
- photosphere where photons radiated into space
what do stars emit radiation of?
- high luminosity
- high peak frequency
increase with temperature
how does a stars life begin?
as clouds of gas, as gravity brings them together, begin denser
gravity pulls gas inwards. as more gas drawn in, gravity increases which compresses gas so it becomes denser forming a protostar
