Question

When a line changes its direction, the angle of the forward line with the external of the preceding line is known as

• A. Azimuth
• B. Dip
• C. Declination
• D. Deflection angle

Hint:

Visualize the angles in a traverse:
- Included Angle: The angle *inside* the traverse, between two adjacent lines.
- Deflection Angle: The angle between the *extension* of the back line and the forward line.

Answer 1

The Correct Option is D

Step 1: Understanding the Question:
The question asks for the name of the angle measured from the extension of the previous line to the next (forward) line in a traverse.

Step 2: Detailed Explanation:
Let's define the angles used in surveying:

• (D) Deflection Angle: This is the angle by which a survey line "deflects" from the prolongation of the preceding line. It is measured either to the right (clockwise) or to the left (counter-clockwise) from the extended previous line. This method is common in route surveys for roads, railways, and pipelines. This perfectly matches the question's description.

• (A) Azimuth: This is the horizontal angle of a line measured clockwise from a reference meridian, usually North. It is a direction, not a change in direction.

• (B) Dip: This is the vertical angle that a magnetic needle makes with the horizontal plane.

• (C) Declination: This is the horizontal angle between the true meridian (True North) and the magnetic meridian (Magnetic North).



Step 3: Final Answer:
The angle of the forward line with the extension of the preceding line is known as the deflection angle.