further physics

Question 1

what are advantages of controlling a telescope from a computer?

Answer 1

• can directly record + process data collected

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Question 2

what are the advantages of the joint venture of international co-operation?

Answer 2

• 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

Question 3

the great canary telescope which allows astronomers to capture distant lights in the universe, can be accessed how?

Answer 3

• directly at the site
• through remote computer control
• through internet

Question 4

what are advantages of space telescopes?

Answer 4

• avoid absorption + refraction effects of atmosphere

- use parts of electromagnetic spectrum that atmosphere absorbs

Question 5

what are the disadvantages of space telescopes?

Answer 5

• expensive

- uncertainties associated with space programmes eg launch delays

Question 6

what are the 2 major

Answer 6

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Question 7

why has Hawaii been proven to be an ideal location?

Answer 7

• high altitude
• isolated location (less poll to interfere with received signal)
• frequent cloudless skies
• equatorial location (best view of solar eclipse)

Question 8

what factors should be considered when planning, building or closing an observatory?

Answer 8

• cost
• environmental impact
• working conditions for employees

Question 9

what can light, water and sound waves all be?

Answer 9

• refracted

- diffracted

Question 10

what is refraction?

Answer 10

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

Question 11

what is diffraction?

Answer 11

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

Question 12

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Answer 12

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Question 13

what is the refraction of white light?

Answer 13

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

Question 14

what is the lunar cycle?

Answer 14

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

Question 15

during the moons orbit around the earth, what are the different faces of the moon?

Answer 15

• dark face (new moon)
• light face (full moon)
• all points in between new moon and full moon

Question 16

explain the earth and the moon?

Answer 16

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

Question 17

what is a solar eclipse?

Answer 17

when moon passes between earth and sun. happens during new moon and results in moon casting shadow on earth

Question 18

what is a total solar eclipse?

Answer 18

when moon directly in front of sun obscures earths view of the sun

observing directly can damage eye.

Question 19

what is a lunar eclipse?

Answer 19

when earth is between sun and moon resulting in earth casting shadow on moon

Question 20

what are extrasolar planets?

Answer 20

planets that orbit star other than sun

Question 21

what is the evidence for the expansion of the universe?

Answer 21

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

Question 22

explain pressure and volume?

Answer 22

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)

Question 23

explain pressure and temperature?

Answer 23

if gas heated up, particles move faster increasing momentum and force they exert when collide

Question 24

explain absolute zero?

Answer 24

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

Question 25

what is absolute temperature?

Answer 25

measure of temp starting at absolute zero

to convert from..

• kelvin to degrees, - 273
• degrees to kelvin, + 273

Question 26

what 3 parts does a star have?

Answer 26

• core hottest part where nuclear fusion takes place
• convective zone where energy in form of photons is transferred
• photosphere where photons radiated into space

Question 27

what do stars emit radiation of?

Answer 27

• high luminosity
• high peak frequency

increase with temperature

Question 28

how does a stars life begin?

Answer 28

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