ASTRON C10 MIDTERM 1 EXAM QUESTIONS WITH
DETAILED VERIFIED ANSWERS (100% CORRECT
ANSWERS) A+ GRADE ASSURED
light year - correct answer-
10*10^12 km almost 10^13, distance light travels in one year, unit of length not time
star - correct answer-self-luminous, gravitationally-
bound, nuclear reactions in core, hot inner parts emit continuous radiation (continuum), cooler outer layer
s absorb wavelengths
planet - correct answer-orbits star, massive -> spherical, not massive to have nuclear reactions in core
kilo - correct answer-thousands
centi - correct answer-hundredth
milli - correct answer-thousandth
mega - correct answer-million
giga - correct answer-billion
micro - correct answer-millionth
nano - correct answer-billionth
AU - correct answer-average distance between earth and sun (150,000,000 km)
speed of light inPa vacuum - correct answer-300,000 orP3*10^5 km/s
,constant of proportionality - correct answer-
1/c, because time is proportional to distance from t=d/c and is t∝d - if tsun ∝ dsun -> tsun = (1/c) * dsun
sun is more distant than moon - correct answer-390x
seconds in a year - correct answer-3.156*10^7 or pi*10^7
nearest star - correct answer-proxima centauri, 4.2ly away
nearest galaxy - correct answer-andromeda, 2.4million ly away
light travels at a speed - correct answer-finite
star crosses meridian (highest arc point in sky) ___ minutes earlier per day - correct answer-4
distance - correct answer-intrinsic brightness vs. appeared brightness
scientific notation rules - correct answer-
to add orPsubtract make sure exponents are same, multiply = add exponents, divide = subtract exponents,
exponentiate = multiply exponents
white light - correct answer-
ordinary sunlight, can see combination of all colors when passed thru aPspectrum
spectroscopy - correct answer-brightness (intensity) as a function of color (wavelength)
Electromagnetic waves consist of - correct answer-oscillating electric and magnetic fields
wavelength - correct answer-distance from one crest to the next
frequency - correct answer-number of times per second a crest passes a fixed plane Q
, period - correct answer-inverse of frequency (1/f) - so if frequency is doubled, periodPis cut in half
1 angstrom - correct answer-0.1 nm
order of colors by wavelength - correct answer-
red (biggest wavelength, 680nm), orange (610nm), yellow (580nm), green (510nm), blue (460nm), violet
(420nm)
order of electromagnetic waves - correct answer-
gamma rays (shortest wavelength), x rays, UV, visible/optical, infrared, microwaves, radio
different speeds of electromagnetic radiation? - correct answer-
no! all electromagnetic waves travel with the same speed c inPa vacuum
mass of a photon - correct answer-none, so inherently follow some curvature
opaque - correct answer-not letting light through
luminosity - correct answer-
total energy emitted per/sec by the entire object, power, proportional to radius squared and temperature to
fourth power (so star can be half temperature and many more times more luminous simply because of size
- surface area very important)
if a star is cooler than a ball, how does the amount of red light produced per unit area by the star compare
to the amount of redPlight produced per unit area of the ball - correct answer-
WHILE wein's law is true that star will peak at larger and redder wavelength because it is cooler, that doe
s not mean star produces more red light. stefan-
boltzmann law tells us that the amount of energy radiated per second per unit area is only proportional to t
he temperature to the fourth power. blackbody that is hotter will radiate more light across whole range of
wavelengths simply because it is hotter (because ball is hotter, it produces more red light per unit area)
if you increase size of the earth - correct answer-
both the distance separating earth and moon and size of moon would increase
DETAILED VERIFIED ANSWERS (100% CORRECT
ANSWERS) A+ GRADE ASSURED
light year - correct answer-
10*10^12 km almost 10^13, distance light travels in one year, unit of length not time
star - correct answer-self-luminous, gravitationally-
bound, nuclear reactions in core, hot inner parts emit continuous radiation (continuum), cooler outer layer
s absorb wavelengths
planet - correct answer-orbits star, massive -> spherical, not massive to have nuclear reactions in core
kilo - correct answer-thousands
centi - correct answer-hundredth
milli - correct answer-thousandth
mega - correct answer-million
giga - correct answer-billion
micro - correct answer-millionth
nano - correct answer-billionth
AU - correct answer-average distance between earth and sun (150,000,000 km)
speed of light inPa vacuum - correct answer-300,000 orP3*10^5 km/s
,constant of proportionality - correct answer-
1/c, because time is proportional to distance from t=d/c and is t∝d - if tsun ∝ dsun -> tsun = (1/c) * dsun
sun is more distant than moon - correct answer-390x
seconds in a year - correct answer-3.156*10^7 or pi*10^7
nearest star - correct answer-proxima centauri, 4.2ly away
nearest galaxy - correct answer-andromeda, 2.4million ly away
light travels at a speed - correct answer-finite
star crosses meridian (highest arc point in sky) ___ minutes earlier per day - correct answer-4
distance - correct answer-intrinsic brightness vs. appeared brightness
scientific notation rules - correct answer-
to add orPsubtract make sure exponents are same, multiply = add exponents, divide = subtract exponents,
exponentiate = multiply exponents
white light - correct answer-
ordinary sunlight, can see combination of all colors when passed thru aPspectrum
spectroscopy - correct answer-brightness (intensity) as a function of color (wavelength)
Electromagnetic waves consist of - correct answer-oscillating electric and magnetic fields
wavelength - correct answer-distance from one crest to the next
frequency - correct answer-number of times per second a crest passes a fixed plane Q
, period - correct answer-inverse of frequency (1/f) - so if frequency is doubled, periodPis cut in half
1 angstrom - correct answer-0.1 nm
order of colors by wavelength - correct answer-
red (biggest wavelength, 680nm), orange (610nm), yellow (580nm), green (510nm), blue (460nm), violet
(420nm)
order of electromagnetic waves - correct answer-
gamma rays (shortest wavelength), x rays, UV, visible/optical, infrared, microwaves, radio
different speeds of electromagnetic radiation? - correct answer-
no! all electromagnetic waves travel with the same speed c inPa vacuum
mass of a photon - correct answer-none, so inherently follow some curvature
opaque - correct answer-not letting light through
luminosity - correct answer-
total energy emitted per/sec by the entire object, power, proportional to radius squared and temperature to
fourth power (so star can be half temperature and many more times more luminous simply because of size
- surface area very important)
if a star is cooler than a ball, how does the amount of red light produced per unit area by the star compare
to the amount of redPlight produced per unit area of the ball - correct answer-
WHILE wein's law is true that star will peak at larger and redder wavelength because it is cooler, that doe
s not mean star produces more red light. stefan-
boltzmann law tells us that the amount of energy radiated per second per unit area is only proportional to t
he temperature to the fourth power. blackbody that is hotter will radiate more light across whole range of
wavelengths simply because it is hotter (because ball is hotter, it produces more red light per unit area)
if you increase size of the earth - correct answer-
both the distance separating earth and moon and size of moon would increase
