問題一覧
1
The angle of dip is the angle between the direction of the earth's magnetic field and the plane of the horizon. What is the angle of dip at the magnetic equator?
0°
2
What do you call a magnetism which is present only when the material is under the influence of an external field?
Induced magnetism
3
It is the process by which a substance, such as iron or steel, becomes magnetized by a magnetic field.
magnetic induction
4
It remains after the magnetizing force is removed.
Residual magnetism
5
The power of magnet to attract an iron is equal throughout its _________.
length
6
It is a housing or a stand that support the compass.
Binnacle
7
This is the bearing measured from the ship’s fore and aft line from 0° to 180° port or starboard.
relative bearing
8
The magnetic field is generated by electric current due to the motion of convection current of molten iron in the earth’s outer core as it is driven by ______.
Heat
9
It is a mark on the surface of the earth where the magnetic line force is directed horizontally or where a magnetic needle is free to rotate on its plane.
Magnetic equator
10
It is defined as an axis that intersects the earth’s surface at two antipodal points.
Dipole
11
When does the ‘positive dip’ of the magnetic dip results from a tendency of the magnet aligning itself with the lines of earth magnetic field is said to be on its position?
When the north end of the compass needle will point downward in the northern hemisphere
12
It is the difference in the earth’s magnetic field in time and location.
Variation
13
In what plane does the magnetized needle of a simple compass rotate?
Horizontal plane
14
It describes the magnetic influence of electrical currents and magnetized materials.
Vector field
15
What is the term used to measure the ability of the material to support the formation of a magnetic field within itself?
permeability
16
What is the term used to define the magnetic unit per volume of a certain material?
intensity
17
It is a term used when a magnetization of a material in response to applied magnetic field is proportional and constant.
susceptibility
18
What object exhibits a strong magnetic field and attracts materials like iron?
magnet
19
Which part of the Earth are considered to have the strongest external magnetic fields?
towards the poles
20
When a magnet attracts a certain metallic object, this type of metal is commonly called ______.
ferromagnetic
21
What is that process when the magnet first magnetizes ferromagnetic material.
magnetic induction
22
Why do we position ourselves at the aft most of the ship prior swinging it in obtaining compass deviation?
To mitigating the direct effect of ship’s own magnetism
23
Which type of magnetism can alter ship’s magnetism making the compass unreliable?
Retentive magnetism
24
Which is the correct compass heading to start with as the first reference point in swinging the ship to obtain the compass deviation?
000 degree
25
How many degrees is the interval in obtaining the compass deviation making 12 turns using the method of “swinging the compass or swinging the ship” from the starting point until it is completed?
30 degrees
26
Which correction is applied in converting a compass course to true course?
Compass error
27
How can you say that the process taken is “correcting” in the application of the compass error?
Converting a compass heading into a true heading
28
It is defined as the amount that the compass is deflected from the magnetic meridian because of the effects of ship’s iron.
Deviation
29
The proper procedure in removing the air bubble from a compass bowl is carried out except.
Open the compass bowl and ventilate the compass for about 5 minutes
30
Which of the following corresponds to NNE of a compass?
22.5°
31
It is a marking on the compass representing the ship’s bow indicating the ship’s course.
Lubber line
32
Which is not included as the magnetic compass corrector in a binnacle
Magnetic rod
33
It is an error induced in a compass by local magnetic field which must be allowed for, along with magnetic declination if accurate bearing are to be calculated.
Magnetic deviation
34
It a line directly plotted and drawn graphically showing the effect of changes in ship’s heading from 000 ̊- 360 ̊.
Deviation curve
35
What is the mathematical process in solving the correct value of the ship’s compass heading which is not shown on the deviation table?
By subtracting first the value of the two ship’s heading and then dividing it and interpolating their value
36
It is defined as the amount that the compass is deflected from the magnetic meridian because of the effects of ship’s iron.
Deviation
37
What method is used in obtaining the compass deviation using two objects such as buoys, beacons align with each other?
The ranges method
38
When can you say that the compass error is East?
If compass is less or least from the true
39
How do you formulate the process of “Uncorrecting”?
Converting the true to compass
40
Which is the correct compass heading to start with as the first reference point in swinging the ship obtaining the compass deviation to its completion in clockwise motion?
000 degree
41
How many degrees is the interval in obtaining the compass deviation making 12 turns using the method of “swinging the compass or swinging the ship” from the starting point until it is completed?
30 degrees
42
Why do we positioned ourselves at the aft most of the ship prior swinging the latter as one of the process in obtaining compass deviation?
Mitigating the direct effect of the ship’s own magnetism on the process
43
How can you justify the question of an ISM auditor (International Safety Management) the cause of the deflection of the magnetic compass needle pointing away from the magnetic meridian?
When the ship’s own magnetic field and a cargo with magnetic properties is combined
44
Which official ship document will you show when an auditor wants to know the vessel’s track of deviation on various compass heading?
Compass variation book
45
Which of the following mathematical process is involved when the compass course has no exact values on the compass deviation table?
Interpolation
46
What is the purpose of compass deviation table?
It is the amount of deviation for which the navigator must compensate to the ship’s compass to steer a magnetic course.
47
What is the importance of compass deviation card?
It is the unresolveable errors that remains between the displayed compass heading and the actual magnetic heading
48
The process in producing a deviation card is to swing the ships magnetic compass and determine the deviation. This can ideally be done _______.
annually
49
What causes a deviation in a compass?
Magnetic influence of some nearby object, such as a metal or an engine.
50
Which regulation of Chapter V of SOLAS requires all ships of 150 GT and over, and all passenger ships to carry a spare magnetic compass or its equivalent?
Regulation 19