A compass has a _____ which points North.

A. magnet

The magnets seen here will _____.

B. attracting

The strongest part of the magnet is at the magnet's _____.

B. poles

_____ are magnets that can be turned on and off.

A. Electromagnets

Where is a compass placed that cannot determine direction?

B. Polar region

Where is the compass placed to determine the best direction?

C. Equator

Magnets have _____ poles.

A. two

Magnets are attracted to objects made of _____.

C. iron

At what distance from the rod is the magnetic pole of the magnet located?

D. 1/12

Where is the compass placed on ships for the most reliable direction?

B. Monkey island
A _____ is an instrument that helps you tell direction.

C. Magnetic compass

An object that has the pulling or pushing force of a magnet is said to be _____.

A. magnetic

When a magnet pulls toward another magnet, we say that these magnets are " " each other.

A. Attracting

Two like poles, like a South and a South, will always _____.

A. repel

The _____ is the amount of push or pull a magnet has.

B. force

_____ magnets can be magnetized, but lose power quickly.

B. Temporary

A push or pull is called a _____.

A. Force

Magnets are said to _____ if they push away from each other.

A. repel

_____ magnets keep their magnetism.

B. Permanent

A compass has a magnet which points _____.

D. north
The area around the magnet that has magnetic force is called the _____.

A. magnetic field

The poles of a magnet are called the _____ pole and the south pole.

A. north

_____ is a rock that is called a natural magnet.

B. Lodestone

Assuming that the length between two poles of a magnet is 2L, the distance from each pole to its
respective end is______.

B. L/12

The line drawing through two poles of a straight magnet is called______.

B. Magnetic axis

Magnetic neutral axis of a magnet is the place where________.

D. the magnetic field strength is effectively zero

Characteristic of magnetic line of force is_______.

C. going from North Pole to South Pole

What is unit of magnetic pole’s force?

D. Dyne

Which formular illustrates the force between two poles?

B. 𝐹 = 𝑚1𝑚2 / 𝜇𝑑²
Field strength at a point on a line passing through the poles of the magnet is calculated by formula-
________.

D. 𝐻 = 2𝑀𝑑 / (𝑑² − 𝑙²)

Field strength at a point on a line bisecting the magnet at right angles is calculated by formula-
________.

A. 𝐻 = 𝑀 / (𝑑² + 𝑙²)³/²

The North pole end of a magnet is usually painted________.

C. red

Position of North Magnetic Pole________.

B. closes to North Geographical Pole

Magnetic Variation at a certain place on the earth's surface is the horizontal angle contained
between _______.

B. the true meridian and the direction of the lines of force of the earth’s magnetic field at any place.

Lines joining places on a chart having the same value of Variation are called____.

A. Isogonal Lines

When a compass needle, under the influence of the earth’s magnetic field at a place, points to the
left of True North, the Variation is said to be _______.

D. Westerly.

When a compass needle, under the influence of the earth’s magnetic field at a place, points to the
right of True North, the Variation is said to be _______.

B. Easterly

The vertical angle between the horizontal and the magnetic line of force is the .

E. magnetic dip
The right symbols of the earth’s total force and components of that one are _____.

A. earth’s total force (T), earth's Horizontal Force (H), earth's Vertical Force (Z)

Which force of the earth plays a role in orientating compass needle?

B. earth's Horizontal Force

The magnetic moment depends on______.

C. magnetic field latitude

The greatest directive force is exerted on the magnetic compass when the _______.

A. needles are nearly in line with the meridian

CHƯƠNG 2 NÈ

If a magnetic compass is fixed on wooden or composite ship, its compass needle will orientate
follow______:

B. magnetic meridian

Which component of geographic field does magnetic meridian coincide with?

B. Horizontal component of T

If a magnetic compass is positioning in a magnetized material-manufactured ship, its compass

needle will orientate follow ______?

B. Magnetic meridian

Which is right definition about deviation?

D. is the angle between compass needle and magnetic meridian

If the North end of compass needle is deflected to the right of magnetic meridian, deviation is said
to be…?
A. Easterly

If the North end of compass needle is deflected to the left of magnetic meridian, deviation is said to
be…?

B. Westerly

Which is right definition about magnetic compass error?

A. is the angle between magnetic meridian and compass meridian

Compass needle of a magnetic compass is affected by:

D. Both of above two forces

Passon equation is established to ______?

C. Show the effects of both force of geomagnetic field and force of ship’s magnetic field to compass
needle

Upright position of a vessel means___?

A. Vertical axis of the vessel is perpendicular to horizontal plane

Which effects do the geomagnetic field cause on the magnetic compass?

C. Both of above effects

What is relation ship between horizontal component of force of geomagnetic field (H) and
separated force on fore-and-aft axis (X) of the ship?

A. 𝑋 = 𝐻 cos (360° − 𝑀𝑎𝑔. 𝐶𝑜𝑢𝑟𝑠𝑒)

What is relation ship between horizontal component of force of geomagnetic field (H) and
separated force on athwart ship axis (Y) of the ship?

B. 𝑌 = 𝐻 sin (360° − 𝑀𝑎𝑔. 𝐶𝑜𝑢𝑟𝑠𝑒)

Ship’s permanent magnetism is caused by:

B. the earth's magnetic field affecting the ship's hard iron during construction

What are symbols of components of ship’s permanent magnetism (F) on the compass?

C. (P) the fore and aft component, (Q) the athwart ship component, (R) the athwart ship component

The magnetic compass operates on the principle that:

C. unlike poles attract

Which would influence a magnetic compass?

D. All of the above

Ship’s induced magnetism is caused by______?

A. Magnetized soft iron

Which elements do induced ability of soft iron depend on?

B. Magnetic latitude

Soft iron rods on board are divided into______?

B. Fore-and-aft soft iron, horizontal soft iron, vertical soft iron

Which types of soft iron does fore-and-aft magnetic force (X) of the ship magnetise?

D. Fore-and-aft soft iron

Which types of soft iron does horizontal magnetic force (Y) of the ship magnetise?

A. Horizontal soft iron

Which types of soft iron does vertical magnetic force (Z) of the ship magnetise?

B. Vertical soft iron

Which is total force caused by geomagnetic field and ship’s magnetic field on the fore-and-aft axis
of the ship?

A. 𝑋′ = 𝑋 + 𝑎𝑋 + 𝑏𝑌 + 𝑐𝑍 + 𝑄

Which is total force caused by geomagnetic field and ship’s magnetic field on the athwartship axis
of the ship?

B. 𝑌′ = 𝑌 + 𝑑𝑋 + 𝑒𝑌 + 𝑓𝑍 + 𝑄

Which is total force caused by geomagnetic field and ship’s magnetic field on the athwartship axis
of the ship?

C. 𝑍′ = 𝑍 + 𝑔𝑋 + ℎ𝑌 + 𝑘𝑍 + 𝑅

Which is modified Poisson’s equation on the fore and aft axis?

C. 𝑋′ = 𝑋 + 𝑎𝑋 + 𝑏𝑌 + 𝑐𝑍 + 𝑃

Which is modified Poisson’s equation on the athwartship axis?

B. 𝑌′ = 𝑌 + 𝑑𝑋 + 𝑒𝑌 + 𝑓𝑍 + 𝑄

How many forces are combined from modified Poisson’s equation?

C. 6

Which formula shows relationship between horizontal component of geomagnetic field (H),
magnetic force on fore-and-aft axis (X) and force on athwartship axis (Y)?

B. 𝐻² = 𝑋² + 𝑌²

Which force is created from combination of two components

𝑋
𝑎
+
𝑒
2

a+e

and

𝑌
𝑎
+

𝑒
2

a+e

A. F1

Which force is created from combination of two components

𝑌
𝑑
−

𝑏
2

d−b

2
and

𝑋
𝑑
−

𝑏
2

d−b

C. FB

Which force is created from combination of two components cZ and P?

D. FD

Which force is created from combination of two components fZ and Q?

B. FB

Which force is created from combination of two components

𝑋
𝑎
−

𝑒
2

a−e

2
 and

𝑌
𝑎
−

𝑒
2

a−e

A. FA

Which forces are very small (zero) in following ones?

A. F1 and FC

What is the direction of force H in all heading of the ship?

C. point toward North end of magnetic meridian

What is the direction of force F1 in all heading of the ship?

B. point toward North end of magnetic meridian

What is the direction of force FA in all heading of the ship?

D. is perpendicular to magnetic meridian

What is the direction of force FB in all heading of the ship?

D. is perpendicular to magnetic meridian

What is the direction of force FC in all heading of the ship?

D. is perpendicular to magnetic meridian

What is the direction of force FD in all heading of the ship?

C. 𝛼 = 2𝜃 (𝜃: ship’s magnetic course)

What is the direction of force FE in all heading of the ship?

A. 𝛼 = 𝜃 (𝜃: ship’s magnetic course)

What is regulation about value of

𝜆
=

𝑎
+

𝑒
2

λ=(

1+a+e

) on board vessel?

C. λ = 0.5–0.6

At which value of

𝜆
λ can’t magnetic compass orientate?
A. λ ≤ 0.3

Which is the least force among following ones:

𝐴
′

𝜆
𝐻
,

𝐵
′

𝜆
𝐻
,

𝐶
′

𝜆
𝐻
,

𝐷
′

𝜆
𝐻
,

𝐸
′

𝜆
𝐻
A′λH,B′λH,C′λH,D′λH,E′λH?

A. A′λ𝐻
Which force plays a role as orientation for compass needle?

A. H