Question

A map is prepared with a scale of 1:1000 and a contour interval of 1 m. If the distance between two adjacent contours on the map is 10 mm, the slope of the ground between the adjacent contours is:

• A. 30\%
• B. 10\%
• C. 35\%
• D. 40\%

Hint:

When calculating slope from a map, always convert the map measurements to actual ground measurements using the map scale before calculating the slope percentage.

Answer 1

The Correct Option is B

Step 1: Convert the map distance to actual ground distance. Given the map scale of 1:1000, a distance of 10 mm on the map represents: \[ 10 \text{ mm} \times 1000 = 10,000 \text{ mm} = 10 \text{ m} \text{ on the ground}. \] Step 2: Calculate the slope. The slope \( S \) is calculated as the ratio of the vertical change (contour interval) to the horizontal distance (ground distance), expressed as a percentage: \[ S = \left(\frac{\text{Vertical change}}{\text{Horizontal distance}}\right) \times 100 = \left(\frac{1 \text{ m}}{10 \text{ m}}\right) \times 100 = 10\%. \]