25 extra multiple-choice questions for Thematic Mapping (12th Standard Geography, Samacheer Kalvi), beyond the ones printed in the textbook — each with the correct option highlighted and a clear, worked explanation. Free to read in English and Tamil.
Q1
A map that emphasizes a particular theme or a special topic, such as the average distribution of population of an area, is called a
- A. general reference map
- B. thematic mapCorrect
- C. topographical sheet
- D. relief map
Explanation. The lesson defines a thematic map as a map that emphasizes a particular theme or special topic, such as the average distribution of population of an area.
Q2
In 1854, who created the first thematic map used for problem analysis when he mapped the spread of cholera throughout London?
- A. Dr. L.R. Singh
- B. Ashis Sarkar
- C. John SnowCorrect
- D. Gerardus Mercator
Explanation. The 'Do you know' box says that in 1854 John Snow, a doctor from London, created the first thematic map used for problem analysis when he mapped cholera's spread throughout the city.
Q3
Consider the following statements about thematic maps.
1. They do not just show general features like rivers, cities, political subdivisions and highways.
2. They use a variety of cartographic symbols to depict the spatial pattern of a geographic quality or quantity.
3. They emphasize spatial variation of a very large number of geographic distributions on one map.
Which of the statements given above is/are correct?
- A. 1 only
- B. 1 and 2 onlyCorrect
- C. 2 and 3 only
- D. 1, 2 and 3
Explanation. Thematic maps differ from general reference maps and use cartographic symbols to show spatial patterns. Statement 3 is wrong: they emphasize spatial variation of one or a small number of geographic distributions.
Q4
Which one of the following is NOT a purpose of thematic maps as given in the lesson?
- A. They provide specific information about particular locations
- B. They provide general information about spatial patterns
- C. They can be used to compare patterns on two or more maps
- D. They show only general features such as rivers, cities and highwaysCorrect
Explanation. The three purposes listed are specific information about locations, general information about spatial patterns, and comparison of patterns on two or more maps. Showing only general features is what general reference maps do.
Q5
Pick the odd one out from the five types of thematic map named in the lesson.
- A. Isopleth map
- B. Chorochromatic map
- C. Topographical sheetCorrect
- D. Proportional symbol map
Explanation. The five types of thematic map are choropleth, isopleth, proportional symbol, dot and chorochromatic maps. Topographical sheets are only mentioned as aids useful for drawing a dot map.
Q6
The dot method is a convenient method of representing which kind of data on maps?
- A. Absolute numbersCorrect
- B. Densities per square kilometre
- C. Percentages of the total cropped area
- D. Ratios such as sex ratio
Explanation. The lesson calls the dot method a convenient method of representing absolute numbers on maps. Each dot is assigned a value and the number of dots follows the distribution pattern.
Q7
For which of the following data would the dot method be the right choice?
- A. Population per square kilometre of each district
- B. Literacy rate of each district
- C. Number of cattle given in absolute figures for each administrative unitCorrect
- D. Percentage of area under wheat to the total cropped area
Explanation. Dot maps show the distribution of population, cattle, area under crops and output of commodities when data is given in absolute figures unit-wise. Densities, rates and percentages are shown by choropleth maps.
Q8
According to the lesson, dots of about what diameter may be drawn on a dot map as they are quite effective?
- A. 0.1 to 0.5 mm
- B. 1 to 1.5 mmCorrect
- C. 3 to 5 mm
- D. 5 to 10 mm
Explanation. Dots should be round, of uniform size and small. The lesson says dots of about 1 to 1.5 mm diameter may be drawn as they are quite effective.
Q9
In dot mapping, unproductive lands are called
- A. negative landsCorrect
- B. marginal lands
- C. base lands
- D. administrative lands
Explanation. While placing dots, marshy areas, lakes and river beds are left without dots. The lesson states that such unproductive lands are called negative lands.
Q10
How does the lesson suggest that dots can be kept off negative areas while preparing a dot map?
- A. Negative areas are cut out of the outline map
- B. Negative areas are first shaded lightly with a lead pencil, and the shading is erased after the dots are placedCorrect
- C. Negative areas are given larger dots of lower value
- D. Negative areas are shaded dark so that dots are hidden
Explanation. It is better if negative areas are first identified and shaded lightly with a lead pencil, so dots are not placed there. The pencil shading is erased with a rubber after the dots are placed.
Q11
While placing dots according to the geographic conditions of an area, which of the following are left without dots as negative areas?
- A. Areas with the highest values in the data
- B. Boundaries of the administrative divisions
- C. Marshy areas, lakes and river bedsCorrect
- D. Areas with the most settlements
Explanation. Placing of dots should conform to geographic conditions. Marshy areas and areas occupied by lakes and river beds, being negative, are left without dots on the map.
Q12
For greater accuracy in a dot map, the administrative divisions shown on the outline map should be
- A. as large as possible
- B. as small as possibleCorrect
- C. of exactly equal area
- D. limited to five categories
Explanation. A dot map needs an outline map showing administrative boundaries. For greater accuracy, the lesson advises having the administrative divisions as small as possible.
Q13
Assertion (A): The shape and size of dots must be decided carefully before a dot map is drawn.
Reason (R): Dots that are too small produce an overly sparse dot pattern which is not very precise.
- A. Both A and R are true and R is the correct explanation of ACorrect
- B. Both A and R are true but R is not the correct explanation of A
- C. A is true but R is false
- D. A is false but R is true
Explanation. One step in constructing a dot map is deciding an appropriate dot shape and size. The lesson gives the reason: dots that are too small produce an overly sparse pattern which is not very precise.
Q14
In Example 11.1, one dot represents 1,000,000 persons. Tamil Nadu's population is 76,481,545. How many dots are placed for Tamil Nadu?
- A. 7
- B. 76Correct
- C. 765
- D. 7648
Explanation. Number of dots = 76,481,545 / 1,000,000 = 76.48, so 76 dots are placed, as shown in the book's calculation table for Tamil Nadu.
Q15
The exercise gives the area under sugarcane in Villupuram as 73,243 hectares. If one dot is taken to represent 1,000 hectares, how many dots should be placed for Villupuram?
- A. 7
- B. 73Correct
- C. 732
- D. 7324
Explanation. Following the method of Example 11.1, the area is divided by the dot value: 73,243 / 1,000 = 73.243, so 73 dots are placed within the Villupuram district boundary.
Q16
In a choropleth map, how are density patterns highlighted?
- A. Light shading for high density and dark shading for low density
- B. Light shading for low density and dark shading for high densityCorrect
- C. Large dots for high density and small dots for low density
- D. Lines joining places of equal value
Explanation. The choropleth map uses shades or tints to show intensity. Density patterns are highlighted by light shading for low density and dark shading for high density.
Q17
Consider the following statements about choropleth maps.
1. Shading conforms to administrative units, which form the basis of spatial distribution of data.
2. They can show the percentage of area under wheat cultivation to the total cropped area.
3. They are drawn mainly to show absolute numbers such as the total number of cattle.
Which of the statements given above is/are correct?
- A. 1 and 2 onlyCorrect
- B. 2 and 3 only
- C. 1 and 3 only
- D. 1, 2 and 3
Explanation. Choropleth maps take administrative units as the basis, so shading conforms to them, and they also show percentages such as area under wheat. Absolute numbers like cattle are shown by the dot method.
Q18
Match List I with List II.
A. Dot method - 1. Unproductive lands
B. Choropleth method - 2. First thematic map for problem analysis
C. Negative lands - 3. Absolute numbers
D. John Snow's cholera map - 4. Densities per unit area within political divisions
- A. A-3, B-4, C-1, D-2Correct
- B. A-4, B-3, C-1, D-2
- C. A-3, B-4, C-2, D-1
- D. A-1, B-4, C-3, D-2
Explanation. The dot method represents absolute numbers; choropleth maps represent densities per unit area within political divisions; unproductive lands are called negative lands; John Snow's 1854 cholera map was the first thematic map for problem analysis.
Q19
While interpreting a choropleth map, the value of each shade used on the map can be verified by reading the map's
- A. legendCorrect
- B. scale bar
- C. title
- D. north arrow
Explanation. The second step in interpreting a choropleth is to verify the value of each shade used on the map. The lesson says this can be done by reading the map's legend.
Q20
While drawing a choropleth map, into how many categories is the data grouped, from very high to very low concentration?
- A. 3
- B. 4
- C. 5Correct
- D. 10
Explanation. The data is grouped into 5 categories to represent very high, high, medium, low and very low concentrations. The interval is found as Range/5.
Q21
In drawing a choropleth map, the interval between the categories may be identified by which formula?
- A. Range/5, where Range = maximum value + minimum value
- B. Range/10, where Range = maximum value - minimum value
- C. Range/5, where Range = maximum value - minimum valueCorrect
- D. Total value/5
Explanation. The lesson states that the interval between the categories may be identified as Range/5, where Range = maximum value - minimum value, giving five categories from very low to very high.
Q22
In Example 11.2 on the literacy rate of Tamil Nadu (2011), Kanyakumari has the highest rate (91.75%) and Dharmapuri the lowest (68.54%). What is the range of the data?
- A. 23.21Correct
- B. 22.79
- C. 160.29
- D. 4.64
Explanation. Range = maximum value - minimum value = 91.75 - 68.54 = 23.21, as worked out in step (b) of the book's construction.
Q23
In the choropleth categories of Example 11.2, which district falls in the 'Very High (Above 85)' literacy category?
- A. Kancheepuram
- B. ThoothukudiCorrect
- C. Madurai
- D. Vellore
Explanation. The Very High category (above 85) has Thoothukudi, The Nilgiris, Kanyakumari and Chennai. Kancheepuram and Madurai fall in High (80-85), and Vellore in Medium (75-80).
Q24
The exercise data on area under sugarcane (2015-2016) has a maximum of 73,243 hectares (Villupuram) and a minimum of 14,268 hectares (Namakkal). Using Range/5, what is the interval between categories?
- A. 58,975 hectares
- B. 11,795 hectaresCorrect
- C. 17,502 hectares
- D. 14,649 hectares
Explanation. The book gives Range as maximum value minus minimum value: 73,243 - 14,268 = 58,975 hectares. The interval between categories is Range/5 = 58,975 / 5 = 11,795 hectares.
Q25
Arrange the steps to construct a dot map in the correct order.
1. Determine an appropriate dot shape and size
2. Obtain a base map of the area or administrative regions
3. Place the correct number of dots within each administrative boundary
4. Study the data and decide on a dot value
- A. 2, 4, 1, 3Correct
- B. 4, 2, 1, 3
- C. 2, 1, 4, 3
- D. 4, 1, 2, 3
Explanation. The lesson lists the steps as: obtain a base map, study the data and decide a rounded dot value, determine dot shape and size, then place the correct number of dots in each administrative boundary.
