Absorption lines due to interstellar gas
a. are wider than the lines from stars because the gas is hotter than most stars.
b. are narrower than the lines from stars because the gas has a lower pressure than stars.
c. indicate that the interstellar medium contains dust.
d. indicate that the interstellar medium is expanding away from the Sun.
e. None of the other choices are correct.
b
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If an electron is accelerated from rest through a potential difference of 300 V, find its approximate speed at the end of this process. (e = 1.6 × 10^-19 C; me = 9.1 × 10^-31 kg)
a. 2.5 × 10^7 m/s c. 1.0 × 10^7 m/s b. 2.1 × 10^7 m/s d. 1.4 × 10^7 m/s
Calculate the current through a 10.0-m long 22 gauge (having radius 0.321 mm) nichrome wire if it is connected to a 12.0-V battery
The resistivity of nichrome is 100 × 10-8 ? ? m. A) 776 mA B) 30.9 A C) 17.5 A D) 388 mA E) 61.8 A
All stars are born with the same basic composition, yet stars can differ greatly in appearance. Which two factors are most important in determining the current appearance of a star?
A) mass and stage of life B) luminosity and stage of life C) age and location in the galaxy D) mass and surface temperature E) apparent brightness and luminosity
Which is longer, the sidereal or solar day? By how much?
What will be an ideal response?