Which of the following is a problem inherent in all large radio telescopes?
A) They are badly affected by poor seeing and atmospheric turbulence.
B) The lightest breeze shakes them, making the observations blurry.
C) Their waves are blocked by water vapor, so they must be located in deserts.
D) Radio waves have long wavelengths, so radio telescopes have poor resolution.
E) The dust clouds in the Milky Way block almost all wavelengths except light.
D
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The temperature at which ferromagnetic materials transform into paramagnetic materials is called the
A. Celsius temperature. B. Carnot temperature. C. crossover temperature. D. Curie temperature. E. chaos temperature.
The critical angle for an air-glass interface is 10.9 degrees. A ray in air is incident on the interface. The reflected ray is 100 percent polarized. The angle of refraction is closest to:
A) 10.7° B) 10.1° C) 9.51° D) 8.91° E) 8.31°
The magnetic polarities of sunspots _______________ at the end of an 11-year cycle
Fill in the blank(s) with correct word
In case-hardening, carbon is diffused into low-carbon iron to produce a hard surface layer that resists wear and deformation. At a temperature of 600°C it is observed that the hardened surface layer extends 0.001 meter into the surface of the iron after exposure to carbon for two hours. It is desired to have the hardened surface layer extend 0.002 meters into the iron. At 600°C how many hours of carburizing are required?
What will be an ideal response?