Why are Cepheid variables important to understanding the formation of the Universe?
A) Because they rotate at known speeds.
B) Because their brightness is a function of distance from Earth.
C) Because their luminosity is a function of their pulsation period.
D) Because they are at known distances from Earth.
Ans:
B) Because their brightness is a function of distance from Earth.
C) Because their luminosity is a function of their pulsation period.
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What is V?
A. 1.0 MV B. 2.0 MV C. 1.6 MV D. 3.2 MV E. 0.51 MV
What is the energy of an incident photon that is just enough to excite a hydrogen atom from its ground state to its n = 4 state?
A) 12.75 eV B) 10.20 eV C) 3.40 eV D) 0.85 eV
Alpha particles and beta particles are deflected by a magnetic field in
A) opposite directions. B) perpendicular directions to each other. C) the same direction.
Which part of the electromagnetic spectrum has the shortest wavelength?
A) radio B) infrared C) ultraviolet D) visible E) gamma