超星 - 专业英语自测

A. They have a linear dependency.
B. The two currents are separated but interrelated via the space charges.
C. Tube current changes with the supplied tube voltage at constant filament current.
D. Tube current is measured in mA and filament current in A.

查看答案

单选题

The purpose of an x-ray tube filament found in an x-ray circuit is to___.

Allow the current to flow in one direction only.
B. Increase or decrease voltage.
Create thermionic emission.
D. Measure tube current.

查看答案

单选题

The reasons to have two filaments within one tube are followings except____.

A small filament for better geometric resolution.
B. Two filaments for robustness of the tube.
C. A large filament for higher output.
D. To acquire desirable image quality for various subjects.

查看答案

单选题

The followings are main functions of X-ray tube except_____.

A. Conversion of electric energy to X-ray.
B. Conversion of electric energy to heat.
C. Fixation of collimator.
D. Connection for high-tension cables.

查看答案

单选题

Tungsten will melt at what degree?

A. 3000°C
B. 3000°F
C. 3400°F
D. 3400°C

查看答案