The redness of the lunar eclipse is due to
A) refraction of sunsets and sunrises all around Earth.
B) infrared light continually emitted by the Moon.
C) scattering of lower frequencies of light by the Moon.
D) dim light that is incident upon the Moon by Jupiter and other planets.
Answer: A
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What is the highest order (the m value) of the complete visible spectrum (390 nm to 710 nm) that can be obtained with a grating having 300 lines/mm?
a. 5 c. 8 b. 9 d. 4
Rotational Kinetic Energy: A solid sphere, solid cylinder, and a hollow pipe all have equal masses and radii. If the three of them are released simultaneously at the top of an inclined plane and do not slip, which one will reach the bottom first?
A. sphere B. pipe C. cylinder D. The pipe and cylinder arrive together before the sphere. E. They all reach the bottom at the same time.
Which of the following models best explains why our galaxy has spiral arms?
A) The spiral arms are a wave of star formation caused by a wave of density propagating outward through the disk of the galaxy. B) The spiral arms are composed of groups of stars that are bound together by gravity and therefore always stay together as the galaxy rotates. C) The spiral arms were imprinted on the galaxy at its birth. Ever since, like a coiling rope, the spiral arms have been wound tighter with each galactic rotation. D) No model can explain the existence of the arms, which rotate with the galaxy like the fins of a giant pinwheel toy.
A 1.2-kg mass is projected up a rough circular track (radius = 0.80 m) as shown. The speed of the mass at point A is 8.4 m/s, and at point B, it is 5.6 m/s. What is the change in mechanical energy between A and B caused by the force of friction?
A. ?2.7 J B. ?8.8 J C. ?4.7 J D. ?6.7 J E. ?19 J