Chapter Name: Contours
Give the terms used in contours for each of the following
Question 1
A number preceded by a dot.
Answer
Spot height
Question 2
The numerical difference between two contour lines.
Answer
Vertical interval
Question 3
A number preceded by a triangle.
Answer
Triangulation point
Question 4
The difference between maximum and minimum height in areas of steep slope.
Answer
Relative height
Question 5
The accurate height of some point marked above the ground.
Answer
Spot height
Describe the following terms
Question 1
Contour Interval
Answer
Contour interval means the difference of height between two consecutive contours. For example, if one thick contour shows the height 300 metres and the next thin contour depicts the height of 320 metres. Then, the contour interval is 20 metres.
Question 2
Vertical Interval
Answer
The vertical distance between any two contour lines is called vertical interval.
Question 3
Horizontal Equivalent
Answer
The actual distance between two points on two contour lines is called horizontal equivalent.
Question 4
Gradient
Answer
The ratio between the vertical height and the horizontal distance of a slope of land measured along the ground is called gradient.
Explain how would you distinguish between the following on the basis of contours
Question 1
Gentle Slope and Steep Slope
Answer
| Gentle Slope | Steep Slope |
|---|---|
| In gentle slopes, the change of elevation is gradual. Normally about 1:25 gradient of elevation is gradual. | Steep slope suddenly slopes up or down. |
| The contours are placed wide apart in gentle slope. | For steep slopes, the contours are drawn close to one another. |
Question 2
Scarp and Dip
Answer
| Scarp | Dip |
|---|---|
| A scarp has a narrow top with a steep slope. | A dip has a narrow top with a gentle slope. |
| The contour lines are closer to each other. | The contour lines are spread far apart. |
| It has a gradient of 1:3. | It has a gradient of about 1:12. |
Question 3
Ridge and Water Divide
Answer
| Ridge | Water Divide |
|---|---|
| It is a long and narrow highland sloping steeply downwards on its sides. | A line which separates two adjacent drainage basins is known as water divide. |
| Contours showing a ridge are elongated and are closely spaced. | The side on which the ridge is steeper, the contours are drawn closely together, whereas the side on which the ridge is gentle, the contours are drawn far apart. |
Short Answer Questions
Question 1
What is a ‘contour’?
Answer
Contour lines are imaginary lines which are drawn on a map to join places having the same height above the mean sea level.
Question 2
Give two points of difference between Bench Mark and Spot Height.
Answer
| Bench Mark | Spot Height |
|---|---|
| These are marks etched on stone or a building to indicate the accurate height determined by surveys. | It refers to the height of a point on the ground above the mean sea level. |
| It is written as “BM” followed by a number. | It is represented by a dot followed by a number on the map. |
Question 3
What do you understand by V.I. and H.E.?
Answer
V.I. stands for the vertical interval. It is the vertical distance between any two contour lines.
H.E. stands for a horizontal equivalent. It is the actual distance between two points on two contour lines.
Question 4
What advantages do contours have over hill-shading and hachuring?
Answer
Hill shading and hachuring only give an impression of the slope but do not indicate the heights of the land above sea level, whereas the contours show both impression of the slope as well as the heights of the land above the sea level.
Question 5
Why do two contours never intersect each other?
Answer
Two contours never intersect each other because each line represents a separate elevation, and we can’t have two different elevations at the same point.
Structured Questions
Question 1
What is meant by relief?
Answer
Relief refers to actual configuration of land which includes its altitude and slope. The relief features found on the earth’s surface include mountains, valleys, hills, plains and plateaus.
Question 2
State the three methods used to show the earth’s relief features.
Answer
The three methods used to show the earth’s relief features are-
- hachures
- hill shading
- contours
Question 3
What do the contour lines represent?
Answer
Contour lines are imaginary lines joining places which have the same height above mean sea level.
Question 4
How do contour lines show different slopes of land?
Answer
The contour lines are shown by brown colour as thick brown lines and thin brown lines. Contour lines show:
1. Elevation of land: The height of a contour is indicated by figures inserted in a break in the line.
2. Steepness of its slope: When the contours are very close, they represent steep slopes. When they are farther apart, they represent gradually increasing slopes. The absence of contour lines indicates that the land is flat i.e., a low land.
3. Shape of land at various heights: The contour lines indicate the shape of the land. For example, almost circular contours whose value decreases inside represent a lake.
This post is all about the solution of class 10 icse subject geography for chapter 2 Contours
