What is the least common class of star in our galaxy?
A) A-type
B) M-type
C) O-type
D) G-type
C
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Nucleosynthesis
a. is the process by which energy is produced at the center of the galaxy. b. is the process by which hydrogen and helium are converted into heavier elements. c. describes the structure of a globular cluster. d. describes how the magnetic field of the galaxy traps cosmic rays. e. describes the method by which neutral hydrogen produces 21 cm radiation.
A projectile is fired from ground level with a speed of 150 m/s at an angle 30° above the horizontal on an airless planet where g = 10.0 m/s2. What is the horizontal component of its velocity after 4.0 s?
A) 38 m/s B) 75 m/s C) 150 m/s D) 130 m/s E) 35 m/s
One reason for the higher pitch of your voice after you've inhaled some helium is that sound travels
A) slower in helium than in air. B) faster in helium than in air. C) the same speed in helium but with a longer wavelength.
Which of the following general statements about light and Earth's atmosphere is not true?
A) X-rays from the Sun are absorbed in the thermosphere. B) Visible light from the Sun is absorbed in the exosphere. C) Ultraviolet from the Sun is absorbed in the stratosphere. D) Infrared light emitted by Earth itself is absorbed in the troposphere.