When the magnetic bearing of the sun at noon is 185°20', the magnetic declination will be

Explanation:

Magnetic Declination and Magnetic Bearing of the Sun

Definition: Magnetic declination is the angle between the geographic north (true north) and the magnetic north at a specific location. It is an essential parameter in navigation and surveying as it helps correct compass readings. Magnetic declination can be either east or west depending on whether the magnetic north is to the east or west of true north. The magnetic bearing of the sun is the direction to the sun, measured clockwise from the magnetic north.

Given Scenario: In the problem, the magnetic bearing of the sun at noon is 185°20'. At noon, the sun is due south in the sky when viewed from the northern hemisphere. The magnetic declination is calculated by comparing the magnetic bearing of the sun with its true bearing (geographic direction).

Calculation:

At noon, the sun’s true bearing is 180° (due south). However, the magnetic bearing of the sun is given as 185°20'. This means the compass is reading a direction that is west of the true bearing.

To find the magnetic declination:

• Magnetic Declination = Magnetic Bearing - True Bearing
• Magnetic Declination = 185°20' - 180°
• Magnetic Declination = 5°20' West

The declination is west because the magnetic bearing is greater than the true bearing, indicating that the magnetic north is west of true north.