The suitable contour interval for a map depends on the scale of the map and the level of detail required. In this case, the map scale is given as 1:10000.

Understanding Scale:
The scale of a map indicates the ratio of distances on the map to the actual distances on the ground. For example, a scale of 1:10000 means that one unit of measurement on the map represents 10000 units of measurement on the ground.

Importance of Contour Intervals:
Contour intervals are the vertical distance between contour lines on a topographic map. Contour lines connect points of equal elevation, allowing us to visualize the shape and relief of the land. The contour interval determines the level of detail shown on the map.

Choosing the Suitable Contour Interval:
To choose the suitable contour interval for a map, we need to consider the scale of the map and the level of detail required.

Scale of 1:10000:
A scale of 1:10000 represents a relatively large area with a high level of detail. It means that one unit on the map represents 10000 units on the ground.

Suitable Contour Interval:
For a map with a scale of 1:10000, a contour interval of 2 meters would be suitable.

- A contour interval of 2 meters provides a high level of detail, allowing for accurate representation of the landforms and terrain features.
- With a smaller contour interval, the map will show more contour lines, resulting in a more detailed depiction of the topography.
- This level of detail is appropriate for many applications, such as urban planning, engineering design, and land development.

Other Options:
The other options provided in the question are 5 m, 10 m, and 20 m.

- A contour interval of 5 meters would provide less detail compared to 2 meters. It would result in fewer contour lines on the map, leading to a less accurate representation of the terrain.
- Contour intervals of 10 meters and 20 meters would provide even less detail, suitable for larger-scale maps or general overview purposes. However, they would not be suitable for a map with a scale of 1:10000, which requires a higher level of detail.

Therefore, option 'A' with a contour interval of 2 m is the correct answer for a map with a scale of 1:10000.

Since the contour interval in inversly proposnal to the scale of the map.
it also has the direct formula which is 25/no of cm in 1 km
answer must be 2.5 but the nearest value is 2 m.