Refracting Telescope: A telescope has an angular magnification of 250 when used with a 20 mm eyepiece. What is the focal length of the objective lens?
A. 5.0 cm
B. 25 m
C. 5000 cm
D. 5.0 m
E. 2.5 m
Answer: D
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When counting particle-in-a-box quantum states in three dimensions, why do we divide the “volume” of only one eighth of a full spherical shell by the “volume” per quantum state? Why not the full shell’s volume?
A. Molecules in a gas can only have positive momentum components. B. A single quantum energy state embraces both positive and negative values for each momentum component. C. A particle’s momentum magnitude must be positive. D. The factor of 2 in the expression h/2L already counts both possible momentum signs. E. We really do include the full shell: the diagram only shows 1/8 of the shell to make it easier to draw. F. Some other reason (specify).
Three spaceships A, B, and C are in motion as shown in the figure. The commander on ship B observes ship C approaching with a relative velocity of 0.83c
The commander also observes ship A, advancing in the rear, with a relative velocity of 0.48c. As measured by commander on ship B, at what speed is ship A approaching ship C? A) 1.3c B) 0.94c C) 0.25c D) 0.58c E) 2.2c
The grooves and ridges on Ganymede are thought to
A) be due to the moon's rapid rotation. B) have grown considerably larger since the Voyager spacecraft discovered them. C) be part of an ongoing volcanic process. D) be due to crustal tectonics motion (plate tectonics). E) have formed within the last thousand years.
The ripple frequency of a bridge rectifier is
a. double the input frequency. b. the same as the input frequency c. triple the input frequency. d. quadruple the input frequency.