What is the hardness of quartz on the Mohs scale?
a. 1
b. 4
c. 7
d. 10
c
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Which is correct?
A.) 24 different kinds of quarks. B.) 12 kinds of quarks and the corresponding 12 kinds of antiquarks. C.) 24 kinds of antileptons. D.) 6 kinds of quarks and the corresponding 6 antiquarks, and 6 kinds of leptons and their 6 corresponding antileptons. E.) 3 quarks and the corresponding 3 antiquarks, 3 leptons and the corresponding 3 antileptons, and 12 other antileptons.
What condition is necessary in an interstellar gas cloud for it to begin collapsing?
A) a low density B) a low temperature C) a high temperature D) a high heavy element content E) a low heavy element content
Suppose you place your face in front of a concave mirror. Which one of the following statements is correct?
A) If you position yourself between the center of curvature and the focal point of the mirror, you will not be able to see a sharp image of your face. B) No matter where you place yourself, a real image will be formed. C) Your image will always be inverted. D) Your image will be diminished in size. E) None of these statements are true.
Light from an object near the event horizon received by a distant observer is ________
Fill in the blank(s) with correct word