人眼可分辨的最小距离为0.1mm,照射光的波长为550nm,欲观察0.25μm的细节,显微镜的数值孔径应是: A: 1.0 B: 1.112 C: 1.342 D: 1.574
人眼可分辨的最小距离为0.1mm,照射光的波长为550nm,欲观察0.25μm的细节,显微镜的数值孔径应是: A: 1.0 B: 1.112 C: 1.342 D: 1.574
A compressible fluid is flowing through a pipe with a constriction. The diameter of the narrow section is 0.8000 the diameter of the wide section. The velocity of the fluid in the narrow section is 1.700 the velocity of the fluid in the wide section. If the density of the compressible fluid is 1.200 kg/m3 in the narrow section, then what is the density of the fluid in the wide section? A: 1.112 kg/m3 B: 1.256 kg/m3 C: 1.300 kg/m3 D: 1.333 kg/m3 E: 1.400 kg/m3
A compressible fluid is flowing through a pipe with a constriction. The diameter of the narrow section is 0.8000 the diameter of the wide section. The velocity of the fluid in the narrow section is 1.700 the velocity of the fluid in the wide section. If the density of the compressible fluid is 1.200 kg/m3 in the narrow section, then what is the density of the fluid in the wide section? A: 1.112 kg/m3 B: 1.256 kg/m3 C: 1.300 kg/m3 D: 1.333 kg/m3 E: 1.400 kg/m3
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