During one phase of the big bang, gamma ray photons were creating electrons and positrons (anti-electrons). At this time, the Universe also contained ____
a. protons and antiprotons
b. protons and neutrons
c. neutrons only
d. no other matter or antimatter
e. neutral atoms
b
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The rms speed of the molecules of a gas is 200 m/s at a temperature 300 K. What is the rms speed of the molecules at 500 K?
A) 155 m/s B) 333 m/s C) 258 m/s D) 556 m/s E) 800 m/s
Alpha titanium alloys with concentrations of aluminum greater than 5 percent can be precipitation-hardened with the precipitate _________.
Fill in the blank(s) with the appropriate word(s).
If the z-component of the magnetic field of an electromagnetic wave traveling in the +x direction through vacuum obeys the equation
Bz(x, t) = (1.25 ?T) cos[(3800 m-1)x - (1.14 × 10-12 rad/s)t], what is the largest that the y component of the electric field can be? (c = 3.0 × 108 m/s) A) 375 N/C B) 4.17 × 10-15 N/C C) 3.75 × 108 N/C D) 4.17 × 10-9 N/C E) 1.25 × 106 N/C
Two thermometers are calibrated, one in degrees Celsius and the other in degrees Fahrenheit. At what temperature (in kelvins) do their readings measure the same temperature?
a. 218.15 b. 233.15 c. 273.15 d. 40.15 e. 0