Chapter 2 : Direction

Question 1

When refering to Earth’s Magnetic field, what is ‘T’?

Answer 1

‘T’ is the direction in which the Earth’s magnetic field is acting.

Question 2

How can we resolve ‘T’

Answer 2

‘T’ can be resolved into -

• ‘H’ Horizontal component of Earth’s magnetic field.
• ‘Z’ Verticial component of Earth’s magnetic field.

Question 3

What does an a/c magnetic compass detect?

Answer 3

A/c compass is designed to detect, ‘H’ the horizontal component of Earth’s magnetic field.

Question 4

What is ‘Angle of Dip’?

Answer 4

The angle between ‘H’ and ‘T’ is called Angle of Dip.

Question 5

QB: What is Magnetic Variation?

Answer 5

Angular difference between True North and Magnetic North.

Measured in degrees.

Denoted East or West OF True North.

Question 6

Magnetic North West of True North; Variation -

Answer 6

West

Question 7

Magnetic North East of True North; Variation -

Answer 7

East

Question 8

QB: Thumb rule to derive Magnetic North with Variation given -

Answer 8

Variation West - Magnetic BEST: T.H. + V. West = M.H.

Variation East - Magnetic LEAST: T.H. - V. East = M.H.

Question 9

QB: What is Deviation?

Answer 9

Deviation is the angle between Magnetic North and Compass North.

Measured in Degrees.

Denoted East or West of Magnetic North.

Question 10

Thumb rule to derive Compass North with Deviation given -

Answer 10

Deviation West - Compass BEST: M.H. + D. West = C.H.

Deviation Esat - Compass LEAST: M.H. - D. East = C.H.

Question 11

CONFUSING -

+ used to Prefix East

• used to Prefix West

Answer 11

CONFUSING -

+ used to Prefix East

• used to Prefix West

Question 12

What is an Isogonal line?

Answer 12

Line joining points of equal variation.