The search for black holes involves searching for
a. single stars that emit large amounts of X-rays.
b. X-ray binaries where the compact companion has a mass in excess of 3 .
c. large spherical regions from which no light is detected.
d. pulsars with periods less than one millisecond.
e. pulsars that are orbited by planets.
B
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Compound Microscope: A microscope has an objective lens of focal length 1.40 mm and an eyepiece of focal length 20.00 mm. It is adjusted for minimum eyestrain for persons with a near point of 25.0 cm. A blood sample is placed 1.50 mm from the objective. The magnitude of the overall magnification is closest to
A. 18. B. 37. C. 180. D. 370.
The solar system contains vast numbers of small bodies, which we call asteroids when they are rocky and comets when they are icy. These small bodies are concentrated in the region(s) of the solar system that we call
A. the Oort cloud B. the comet belt C. the solar corona D. the Kuiper belt E. the Doppler belt F. the asteroid belt
A transformer is to be designed to increase the 30 kV-rms output of a generator to the transmission-line voltage of 345 kV-rms. If the primary winding has 80 turns, how many turns must the secondary have?
a. 6 b. 70 c. 920 d. 9200 e. 12
In a delta environment the first grains to settle are
A) light, fine-grained sediment. B) heavier, coarse-grained sediment. C) light, medium-grained sediment. D) heavy and light mixed grains.