An electron vibrating to and fro 1000 times per second generates an electromagnetic wave having a
A) period of 1000 s.
B) speed of 1000 m/s.
C) wavelength of 1000 m.
D) frequency of 1000 Hz.
Answer: D
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Which of the following is not generally true of all the terrestrial world lithospheres?
A) The lithosphere is broken into a set of large plates that float upon the softer rock below. B) Rock in the lithosphere is stronger than rock beneath it. C) The lithosphere extends from somewhere in the mantle all the way to the surface. D) The thickness of the lithosphere depends on interior temperature, with cooler interiors leading to thicker lithospheres.
Which of the following statements about rich clusters of galaxies (those with thousands of galaxies) is not true?
A) They are sources of X-ray emission due to the presence of hot, intergalactic gas. B) There likely have been numerous collisions among the member galaxies at some time in the past. C) Galaxies in the central regions are predominantly spirals, while elliptical galaxies roam the outskirts. D) They often have a very large, central dominant galaxy near their center, perhaps formed by the merger of several individual galaxies. E) The speeds of the galaxies in the cluster indicate that most of the cluster mass is dark matter.
As an aircraft gains altitude, the outside air pressure __________ with height
Fill in the blank(s) with correct word
A solid sphere, a solid cylinder, a spherical shell, and a hoop all have the same mass and radius. Each are rolling on a horizontal surface with the same center of mass speed, and then they roll up identical inclines. Which one goes the greatest distance up its incline?
a. the hoop b. the solid sphere c. the spherical shell d. the cylinder e. They all go the same distance up their inclines.