The interstellar clouds called molecular clouds are
A) the cool clouds in which stars form.
B) the clouds in which elements such as carbon, nitrogen, and oxygen are made.
C) the clouds that are made mostly of complex molecules such as carbon dioxide and sulfur dioxide.
D) the hot clouds of gas expelled by dying stars.
A) the cool clouds in which stars form.
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Matter Waves: If the wavelength of a photon in vacuum is the same as the de Broglie wavelength of an electron, which one is traveling faster through space?
A. The electron because it has more mass. B. The photon because photons always travel through space faster than electrons. C. They both have the same speed.
An inertial frame is one moving with ________ (two words) with respect to the "fixed stars", i.e., with respect to the average position of all matter in the universe.
What will be an ideal response?
The luminosity of the Sun is a measure of
A) the energy received by the Sun on Earth's surface. B) the energy received by the Sun at the location of Earth. C) the energy received by the Sun at any location in the solar system. D) the energy emitted by the Sun at the photosphere. E) the total energy emitted by the Sun in all directions.
What particle is emitted when 236Pa decays to 236U? (The atomic numbers of Pa and U are, respectively, 91 and 92.)
a. beta (positron) c. gamma quantum b. alpha d. beta (electron)