An amateur astronomer grinds a double convex lens whose surfaces have radii of curvature of magnitudes 40 cm and 60 cm. The glass has an index of refraction of 1.54. What is the focal length of this lens when used in the night air?
A) 220 cm B) 43 cm C) 130 cm D) 89 cm E) 44 cm
E
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When a wheel is rolling without slipping, the magnitude of its velocity relative to the ground is greatest at
A. the point in contact with the ground. B. the point at the center of the wheel. C. the point at the top of the wheel opposite to the point in contact with the ground. D. the point farthest forward from the center of mass of the wheel. E. the point farthest behind the center of mass of the wheel.
The study of minerals is called ______________
Fill in the blank(s) with correct word
The Roche lobe of a star in a binary star system:
A) resembles the ear of Edouard Roche, a French mathematician. B) is, in terms of the star's gravity, its "zone of influence." C) is the part of a rapidly rotating star that will eventually spin away to form planets. D) is the accretion disk around the companion star. E) leads to formation of rings, like around the jovian planets.
A sample of an ancient sedimentary rock contains slightly less of the isotope carbon-13 than found in inorganic material. One possible explanation for this is that
A) it was a meteorite that fell from the sky B) some kind of radioactive decay occurred in it in the past C) it used to be at the bottom of an ancient ocean D) some kind of biological activity occurred in it in the past