你可能感興趣的試題

單項(xiàng)選擇題

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

單項(xiàng)選擇題

The Flinders bar on a magnetic compass compensates for the（）.

A.Induced magnetism in vertical soft iron
B.Induced magnetism in horizontal soft iron
C.Permanent magnetism in ship's steel
D.Vessel's inclination from the vertical