Radio maps of our galaxy show spiral arms because
a. the arms have larger Doppler shifts.
b. the gas in the spiral arms is very hot.
c. the dust in spiral arms is denser.
d. the gas in spiral arms is denser.
e. the stars in the spiral arms emit most of their energy at radio wavelengths.
D
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Which of the following statements about the arrangement of movable objects in a space is true?
a. The placement of movable objects can decrease the amount and type of interaction in a space b. The construction of movable objects such as chairs can impact people's willingness to remain in a space, c. The placement of movable objects can increase the amount and type of interaction in a space. d. All of these statements are true:
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What will be an ideal response?
The momentum of 1 J of energy in an electromagnetic wave is
A) 1.5 × 10-9 kg?m/s. B) 3 × 10-9 kg?m/s. C) 1 kg m/s. D) 1 × 10-17 kg?m/s. E) 1000 kg m/s.
In an electroplating process, it is desired to deposit 40 mg of silver on a metal part by using a current of 2.0 A
How long must the current be allowed to run to deposit this much silver? The silver ions are singly charged, and the atomic mass of silver is 108 g/mol. (e = 1.60 × 10-19 C, NA = 6.02 × 1023 atoms/mol) A) 16 s B) 18 s C) 20 s D) 22 s