A large mass-to-light ratio for a galaxy indicates that
A) the galaxy is very massive.
B) the galaxy is not very massive.
C) on average, each solar mass of matter in the galaxy emits less light than our Sun.
D) on average, each solar mass of matter in the galaxy emits more light than our Sun.
E) most stars in the galaxy are more massive than our Sun.
C
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The magnitude of the magnetic field inside a solenoid is inversely proportional to the current flowing through the solenoid
Indicate whether the statement is true or false
Venus and Earth probably formed with similar amounts of carbon dioxide in their secondary atmospheres. Which of the following is true?
a. The majority of Earth's carbon dioxide escaped into space because of its hotter temperature, whereas Venus's carbon dioxide remains gravitationally bound to Venus. b. The majority of Earth's carbon is now bound up in rock, whereas Venus's remains in its atmosphere. c. Earth lost more of its secondary atmosphere because it was bombarded by more planetesimals than Venus. d. The majority of Earth's carbon was absorbed by plants during photosynthesis. e. Earth and Venus still have equal amounts of carbon dioxide in their atmospheres.
Calculate the heat loss through a 1-m *3-m glass window 7-mm-thick if the inner surface temperature is 20°C and the outer surface temperature is 17°C. Comment on the possible effect of radiation on your answer.
IVEN
• Window: 1 m by 3 m
• Thickness (L) = 7 mm = 0.007 m
• Surface temperature
? Inner (Ti) = 20°C
? outer (To) = 17°C
FIND
• The rate of heat loss through the window (q) ASSUMPTIONS
• One dimensional, steady state conduction through the glass
• Constant thermal conductivity
SKETCH
PROPERTIES AND CONSTANTS
Thermal conductivity of glass (k) = 0.81 W/(m K)
The number of cycles of a periodic process that occur per unit time is called the period
Indicate whether the statement is true or false