Some regions along the plane of the Milky Way appear dark because:
A) there are no stars in these areas.
B) stars in that region are hidden by interstellar gas.
C) stars in that region are hidden by dark dust particles.
D) many brown dwarfs in those areas absorb light which they turn into heat.
E) many black holes absorb all light from those directions.
C
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A 50-gram sample of dry ice (solid CO2) is placed in a 4-liter container. The system is sealed and allowed to reach room temperature (20°C). By approximately how much does the pressure inside the container increase when the dry ice turns to gas? (Ignore the initial volume of the sample.)
What will be an ideal response?
Which planet has the most extreme seasons?
A. Jupiter B. Saturn C. Mercury D. Venus E. Uranus
A boy kicks a football from ground level with an initial velocity of 20 m/s at an angle of 30° above the horizontal. How long does it take for the ball to rise to the highest point of its trajectory?
A) 1.0 s B) 1.8 s C) 2.0 s D) 3.5 s E) 0.5 s
Nitrogen gas is heated by a pulsed laser to 50 000 K. If the diameter of the nitrogen atoms is assumed to be 1.0 × 10^?10 m, and the pressure is 1.0 atm, what is the mean free path?
a. 1.5 × 10^?4 m b. 1.5 × 10^?7 m c. 1.5 × 10^?10 m d. 1.5 × 10^?14 m e. 1.5 × 10^?2 m