Has Polaris always been the "North Star" , also known as the "Pole Star" ?
a. No, because the Earth's axis slowly changes the direction it points.
b. No, because it is a young star which formed only a few hundred years ago.
c. Yes, because stars position change little over many centuries.
d. No, because the Milky Way blocked our line of site to it for a long time.
No, because the Earth's axis slowly changes the direction it points.
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What distance method is used to determine the distance to the most distant galaxies when only a redshift is measured?
a. Hubble's law b. supernova observations c. period-luminosity relationship of variable stars d. parallax
The total energy radiated by a blackbody depends on
A) the square of its temperature. B) the fourth power of its temperature. C) the fourth root of its temperature. D) the square root of its temperature. E) the cube of its temperature.
Two long parallel wires placed side-by-side on a horizontal table carry identical size currents in opposite directions. The wire on your right carries current toward you, and the wire on your left carries current away from you
From your point of view, the magnetic field at the point exactly midway between the two wires A) points up. B) points down. C) points toward you. D) points away from you. E) is zero.
What is the complementarity principle?
a. If an electron or photon is a particle, it cannot be a wave. b. If an electron is being observed as a particle, it cannot be simultaneously observed as a wave. c. A complete description of an electron or photon must include its particle and wave characteristics. d. If electrons act as particles in an experiment, then the photons in the experiment behave as waves. e. When an electron or photon is behaving like a particle, it is not behaving like a wave.