航海英语磁罗经与陀螺罗经的使用章节练习(2017.12.10)

单项选择题
The Flinders bar and the quadrantal spheres should be tested for permanent magnetism at what interval（）.
A.They are not subject to permanent magnetism; no check is necessary
B.Semiannually
C.Annually
D.Every five years
单项选择题
The most accurate method of determining gyrocompass error while underway is by（）.
A.Comparing the gyro azimuth of a celestial body with the computed azimuth of the body
B.Comparing the gyro heading with the magnetic compass heading
C.Determining from the chart the course made good between celestial fixes
D.It cannot be determined accurately at sea due to drift of unknown currents
单项选择题
The MOST important feature of the material used for making the binnacle of a standard magnetic compass is that it is（）.
A.nonmagnetic
B.weatherproof
C.corrosion resistant
D.capable of being permanently affixed to the vessel
单项选择题
The magnetism in the various structures of a ship changing as a result of cruising，vibration，or aging is termed（）.
A.permanent magnetism
B.subpermanent magnetism
C.induced magnetism
D.variable magnetism
单项选择题
The compass deviation changes as the vessel changes（）.
A.geographical position
B.speed
C.heading
D.longitude
单项选择题
In more recent years，（）has been used by civilians in many new ways to determine positions，such as in automobile and boat navigation，hiking，emergency rescue，and precision agriculture and mining.
A.GPS
B.GMDSS
C.AIS
D.Navtex
单项选择题
Variation in a compass is caused by（）.
A.worn gears in the compass housing
B.magnetism from the earth's magnetic field
C.magnetism within the vessel
D.lack of oil in the compass bearings
单项选择题
The error in a magnetic compass caused by the vessel’s magnetism is called（）.
A.variation
B.deviation
C.compass error
D.bearing error
单项选择题
When adjusting a magnetic compass using the fore-and-aft permanent magnets，you should（）.
A.use the magnets one at a time，putting one in one side and then one on the opposite side，one step higher
B.use the magnets in pairs，starting at the top，with trays at the highest point of travel
C.use the magnets in pairs，from the bottom up，with the trays at the lowest point of travel
D.fill all the trays with magnets，then remove them one-by-one until the deviation is removed
单项选择题
When a vessel changes course from one cardinal heading to another cardinal heading whilea djusting the compass，which action should be taken?（）
A.The course change should be made rapidly to prevent transient induced magnetism while passing the intercardinal headings
B.After the new heading is reached，the vessel should steam on that course for at least two minutes before the adjustment
C.During the course change，you should gently tap the compass to remove any error caused by friction on the pivot bearing
D.After steadying on the new heading，the compass card should be slewed by a magnet and allowed to oscillate freely to remove any gaussin error