The _______________ time is the amount of time it took light to travel from a celestial object to Earth
Fill in the blank(s) with correct word
lookback
look-back
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What is the energy of a photon that has a wavelength equal to the de Broglie wavelength of a proton having a speed of 7.1 × 104 m/s? (mproton = 1.67 × 10-27 kg, c = 3.00 × 108 m/s)
A) 220 keV B) 150 keV C) 290 keV D) 360 keV E) 440 keV
Solutions are
a. homogeneous mixtures. b. heterogeneous mixtures. c. nonuniform mixtures. d. none of these.
Two factors that greatly affect air resistance on falling objects are frontal area and
A) mass. B) weight. C) speed.
At extremely high temperatures (e.g., millions of degrees), which of the following best describes the phase of matter?
A) a gas of rapidly moving molecules B) a plasma consisting of positively charged ions and free electrons C) a gas consisting of individual, neutral atoms, but no molecules D) a plasma consisting of rapidly moving, neutral atoms E) none of the above (At these extremely high temperatures, matter cannot exist.)