單項(xiàng)選擇題

What is used to correct for both induced and permanent magnetism，and consequently must be readjusted with radical changes in latitude（）.

A.Flinders bar
B.Soft iron spheres
C.Fore-and-aft permanent magnets in their trays
D.Heeling magnet

你可能感興趣的試題

What is the basic principle of the magnetic compass（）.

A.Magnetic materials of the same polarity repel each other and those of opposite polarity attract
B.The Earth's magnetic lines of force are parallel to the surface of the Earth
C.Magnetic meridians connect points of equal magnetic variation
D.The compass needle（s）will，when properly compensated，lie parallel to the isogonic lines of the Earth

單項(xiàng)選擇題

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