Bissoy.com
Doctors Medicines MCQs Q&A

A line PQ in an old map had magnetic bearing of N 57° E when the local magnetic declination was 2°E. If the magnetic declination is now 4°W, what will be the magnetic bearing of the line PQ now?

A line PQ in an old map had magnetic bearing of N 57° E when the local magnetic declination was 2°E. If the magnetic declination is now 4°W, what will be the magnetic bearing of the line PQ now? Correct Answer N 63° E

Concept:

TB (True Bearing) = MB (Magnetic bearing) ± Declination

(Use + ve for eastern and – ve for western declination)

[ alt="F2 N.M. N.J 30-07-2019 D7" src="//storage.googleapis.com/tb-img/production/19/08/F2_N.M._N.J_30-07-2019_D7.png" style="width: 450px; height: 257px;">

Calculation:

[ alt="F4 A.M Madhu 18.05.20 D2" src="//storage.googleapis.com/tb-img/production/20/05/F4_A.M_Madhu_18.05.20_D2.png" style="width: 230px; height: 201px;">

 

[ alt="F4 A.M Madhu 18.05.20 D3" src="//storage.googleapis.com/tb-img/production/20/05/F4_A.M_Madhu_18.05.20_D3.png" style="width: 269px; height: 231px;">

True bearing of a line, TB is given by

TB = Magnetic Bearing (MB) ± Magnetic Declination

Use Positive sign, when Magnetic Declination is towards East and use negative sign when magnetic declination is towards West.

When Magnetic Declination is towards 20 East.

MB = N570 E

TB = 57 + 2 = 590 or N 590 E ( see fig 1)

When Magnetic Declination is towards 40 West.

MB = ?

True bearing of line would not change due to change in Magnetic Meridian.

59 = MB - 4

∴ MB = 630 or N 630 E (see fig 2)

Related Questions

In a region with magnetic declination of 2°E, the magnetic Fore bearing (FB) of a line AB was measured as N79°50’E. There was local attraction at A. TO determined the correct magnetic bearing of the line, a point O was selected at which there was no local attraction. The magnetic FB of line AO and OA were observed to be S52° 40’E and N50°20’W, respectively. What is the true FB of line AB?
A stationery seller has a highlighter pen, a country map, and a world map. The cost of a highlighter pen is Rs. 96. If he sells a pen with a country map, he receives the amount twice the value of the world map. And if he sells a pen with the world map, he receives an amount that is less than the value of the country map by Rs. 210. What is the value of the world map?
The magnetic bearing and declination of a line were recorded in the year 1906 as S 43°30' E and 2° E respectively. If the declination in the year 2006 is 3° W, the magnetic bearing of the line is
Magnetic bearing of a line AB was N 59° 30' W in the year 1967, when the declination was 4° 10' E. If the present declination is 3° W. the whole circle bearing of the line is
Which of the following statements is correct in the context of using map in a classroom? A. Map is a socio-political construct. B. From time immemorial, 'North' has always been shown at the top of a map in all socio-political contexts. C. Map is a three dimensional device whereas we live in a two dimensional world. D. Map is an aid to develop a 'sense of time' in learners. Choose the correct option.
The magnetic bearing of a line is 62°30’. What is the true bearing of the line if the magnetic declination is 3°45’ W?
If the magnetic quadrantal bearing of a line is S 46° 30' W and magnetic declination at that place is 2° 30' E, then true whole circle bearing of that line will be
The magnetic bearing of a line AB is S28°30’E. What is the true bearing of line AB if the magnetic declination is 7°30’ towards west ?
The magnetic bearing of line is 49° 30'. The true bearing of the line if magnetic declination is 4° 30' east is . . . . . . . .
The magnetic bearing of a line AB is 141° 15'. What is the true bearing of the line if the magnetic declination is 8° 15'W.