Which of the following statements is true of protostars?
A) They are luminous red objects.
B) They are smaller than main-sequence stars.
C) They have completely collapsed.
D) They have temperatures that are more than 10,000 K.
A
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You observe a full Moon rising at sunset. What will you see at midnight?
A) a full Moon high in the sky B) a first quarter Moon C) a waning gibbous Moon D) a third quarter Moon
Spectra show that the moons of Uranus contain frozen water, although their surfaces are _______________
Fill in the blank(s) with correct word
A planet is in orbit around the Sun. The semimajor axis of the orbit is 5 AstronomicalUnits (AU). UseP2=a3to calculate the period of the orbit in years.
a) 5 years b) 0.2 years c) 135 years d) 125 years e) 11.2 years
A Young's double-slit apparatus is set up so that a screen is positioned 1.6 m from the double slits, and the spacing between the two slits is 0.0315 mm. What is the distance between alternating bright fringes on the screen if the light source has a wavelength of 630 nm? (1 nm = 10-9 m)
a. 0.016 m c. 0.025 m b. 0.047 m d. 0.032 m