ASTRONOMY C10 EXAM QUESTIONS WITH
DETAILED VERIFIED ANSWERS (100% CORRECT
ANSWERS) A+ GRADE ASSURED 2025-2026
Photosphere CORRECT ANSWER
visibleP"surface" of the sun (lowest level of the atmosphere); where the atmosphere becomes dense
Chromosphere CORRECT ANSWER sun's thin layer; hotter than photosphere; red due to hydrogen
P
emission
Corona CORRECT ANSWER large, low density envelope with lots of x-rays
Solar Wind CORRECT ANSWER
electrons and positive ions streaming from the sun; interacts with planet magnetic fields and with comets
Solar Flare CORRECT ANSWER violent release of energy from the sun
Coronal Mass Ejection CORRECT ANSWER
large outburst that produces auroras in N&S longitudes on earth and can cause power outages
Prominence - correctPanswer-
more gentle eruption on sun's surface: loops of gas above chromosphere, glowing pinkish/red
Sunspots CORRECT ANSWER
black/grey b/c 2000K cooler than surroundings; can measure rotation period of the sun (about 1mo) by m
onitoring long-lived sunspots
Stars CORRECT ANSWER huge opaque luminous balls of gas held together by gravity-
400 billion in milky way only; wavelength at which spectrum peaks = measure of its surface temp
Stellar Spectrum CORRECT
ANSWER Blue: O greater than
30,000K
,B 10,000-30,000
, White:
A 7,500-10,000
F 6,000-7,500
G 5,000-6,000
Red
K 3,500-5,000
M 2,200-3,500
L less than 2,200
Parallax CORRECT ANSWER distance(parsec) =
1/parallax(arc sec) d(pc) = 1/p(arc sec)
angle subtended (covered) by 1AU (half diameter of earth's orbit); if earth to sun distance were longer an
gle would be greater and star further away
Apparent Brightness CORRECT ANSWER b = L/4πrd
energy received from a star, per unit area, per unit time
Inverse Square Law of Light CORRECT ANSWER b = L/4πd^2
luminosity and distance = proportional
Sizes of Stars CORRECT ANSWER L =
4πR^2σT^4 luminosity = (surface area)x(energy
emitted/cm^2-s)
measure T from spectrum, deduce L from brightness & distance, then derive radius R
*as R changes, LPvaries*
DETAILED VERIFIED ANSWERS (100% CORRECT
ANSWERS) A+ GRADE ASSURED 2025-2026
Photosphere CORRECT ANSWER
visibleP"surface" of the sun (lowest level of the atmosphere); where the atmosphere becomes dense
Chromosphere CORRECT ANSWER sun's thin layer; hotter than photosphere; red due to hydrogen
P
emission
Corona CORRECT ANSWER large, low density envelope with lots of x-rays
Solar Wind CORRECT ANSWER
electrons and positive ions streaming from the sun; interacts with planet magnetic fields and with comets
Solar Flare CORRECT ANSWER violent release of energy from the sun
Coronal Mass Ejection CORRECT ANSWER
large outburst that produces auroras in N&S longitudes on earth and can cause power outages
Prominence - correctPanswer-
more gentle eruption on sun's surface: loops of gas above chromosphere, glowing pinkish/red
Sunspots CORRECT ANSWER
black/grey b/c 2000K cooler than surroundings; can measure rotation period of the sun (about 1mo) by m
onitoring long-lived sunspots
Stars CORRECT ANSWER huge opaque luminous balls of gas held together by gravity-
400 billion in milky way only; wavelength at which spectrum peaks = measure of its surface temp
Stellar Spectrum CORRECT
ANSWER Blue: O greater than
30,000K
,B 10,000-30,000
, White:
A 7,500-10,000
F 6,000-7,500
G 5,000-6,000
Red
K 3,500-5,000
M 2,200-3,500
L less than 2,200
Parallax CORRECT ANSWER distance(parsec) =
1/parallax(arc sec) d(pc) = 1/p(arc sec)
angle subtended (covered) by 1AU (half diameter of earth's orbit); if earth to sun distance were longer an
gle would be greater and star further away
Apparent Brightness CORRECT ANSWER b = L/4πrd
energy received from a star, per unit area, per unit time
Inverse Square Law of Light CORRECT ANSWER b = L/4πd^2
luminosity and distance = proportional
Sizes of Stars CORRECT ANSWER L =
4πR^2σT^4 luminosity = (surface area)x(energy
emitted/cm^2-s)
measure T from spectrum, deduce L from brightness & distance, then derive radius R
*as R changes, LPvaries*
