Question

In the planimeter formula for measuring area, A = M (FR – IR ± 10 N) + C, the additive constant is considered when
1. the anchor point is inside the area being measured
2. the anchor point is outside the area being measured
3. the area traced is in clockwise direction
4. the area traced is in anti-clockwise direction

Answer 1

Correct Answer - Option 1 : the anchor point is inside the area being measured

Explanation:

(i) The areas between curved boundaries are also computed by planimeter from the map of the area. Most commonly used is Amsler polar Planimeter.

(ii) The formula for calculating areas of the map by using planimeter.

Area (A) = M × (FR – IR ± 10 N) + C

Where,

M = Multiplying constant

FR = Final reading of Planimeter

IR = Initial Reading

N = Number of times zero of dial pass is index mark

C = Constant marked above scale division on tracing arm (Constant C is used only when the anchor point is placed inside the plan)