25 extra multiple-choice questions for Representation of Geographical Data (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
Rainfall data are commonly represented on maps by lines called
- A. Isotherms
- B. Isobars
- C. IsohyetsCorrect
- D. Contours
Explanation. The introduction states that climatic data like temperature, pressure and rainfall may be represented by isotherms, isobars and isohyets respectively, so rainfall is shown by isohyets.
Q2
Match the climatic element with the line that represents it.
(a) Temperature - 1. Isobars
(b) Pressure - 2. Isohyets
(c) Rainfall - 3. Isotherms
- A. (a)-3, (b)-1, (c)-2Correct
- B. (a)-1, (b)-3, (c)-2
- C. (a)-2, (b)-1, (c)-3
- D. (a)-3, (b)-2, (c)-1
Explanation. Temperature, pressure and rainfall are represented by isotherms, isobars and isohyets respectively, as stated in the introduction of the unit.
Q3
Numerical data or facts collected in a systematic manner to serve some purpose and presented in a tabulated form are called
- A. Statistical diagrams
- B. StatisticsCorrect
- C. Cartograms
- D. Time series
Explanation. The lesson defines statistics as numerical data or facts collected in a systematic manner to serve some purpose and presented in a tabulated form.
Q4
Consider the following statements about statistical diagrams.
1. They enable us to compare figures at a glance.
2. They cast an easily memorable impression on the mind.
3. They enable us to analyse the data and draw inference easily.
Which of the statements given above are correct?
- A. 1 and 2 only
- B. 2 and 3 only
- C. 1 and 3 only
- D. 1, 2 and 3Correct
Explanation. The book lists exactly these three purposes of statistical diagrams: comparing figures at a glance, leaving an easily memorable impression and helping to analyse data and draw inference easily.
Q5
Two-dimensional statistical diagrams are also known as
- A. Volume diagrams
- B. Area diagramsCorrect
- C. Line diagrams
- D. Star diagrams
Explanation. Two-dimensional statistical diagrams are also known as area diagrams, such as squares, rectangles and circles. Volume diagrams are three-dimensional.
Q6
Cube, block piles and spherical diagrams are examples of
- A. One-dimensional diagrams
- B. Two-dimensional diagrams
- C. Three-dimensional diagramsCorrect
- D. Line graphs
Explanation. Three-dimensional statistical diagrams, also called volume diagrams, include cube, block piles and spherical diagrams.
Q7
Pick the odd one out on the basis of the dimension of the statistical diagram.
- A. Line graph
- B. Bar diagram
- C. Pie diagramCorrect
- D. Histogram
Explanation. Line graph, bar diagram and histogram are one-dimensional diagrams. Divided circles, also called pie diagrams, are two-dimensional (area) diagrams.
Q8
Line graphs are usually drawn to represent
- A. Time series dataCorrect
- B. Regional variations on a map
- C. Proportions of a whole
- D. Volumes of solids
Explanation. The lesson states that line graphs are usually drawn to represent time series data related to temperature, rainfall, population, birth rates and death rates.
Q9
While constructing a line graph, the point where the x-axis and the y-axis intersect at right angles is the starting point. It is normally assigned the value
- A. One (1)
- B. Ten (10)
- C. Zero (0)Correct
- D. Hundred (100)
Explanation. Step 1 of constructing a line graph: the point where the x-axis and y-axis intersect at right angles is the starting point and is normally assigned the value zero (0).
Q10
Arrange the steps of constructing a line graph in the correct order.
1. Plot the data points.
2. Add a title.
3. Draw the x-axis and the y-axis.
4. Draw a line through the plotted points.
5. Add label and scale for both axes.
- A. 3, 5, 1, 4, 2Correct
- B. 3, 1, 5, 4, 2
- C. 5, 3, 1, 2, 4
- D. 3, 5, 4, 1, 2
Explanation. The book's order is: draw the axes, add label and scale for both axes, plot the data points, draw a line through the plotted points and finally add a title.
Q11
A simple line graph represents
- A. the share of each component in a total
- B. the successive changes in the value of one variable over a certain period of timeCorrect
- C. two or more variables compared at the same time
- D. the regional variation of a quantity on a map
Explanation. A simple line graph joins points plotted with two co-ordinates and represents the successive changes in the value of one variable over a certain period of time.
Q12
A line graph in which two or more variables are shown by an equal number of lines for an immediate comparison is called a
- A. Simple line graph
- B. PolygraphCorrect
- C. Multiple bar diagram
- D. Pie diagram
Explanation. A polygraph is a line graph in which two or more variables, such as birth rates, death rates and life expectancy, are shown by an equal number of lines for immediate comparison.
Q13
In a polygraph, the line pattern (.-.-.) indicates
- A. a straight line
- B. a broken line
- C. a dotted line
- D. a combination of dotted and broken lineCorrect
Explanation. The book lists straight line, broken line (---), dotted line (.....) and a combination of dotted and broken line (.-.-.) as patterns used to show different variables in a polygraph.
Q14
In the line graph of India's literacy rate (Census 2011), the rate was 64.83% in 2001 and 74.04% in 2011. By how many percentage points did it rise in this decade?
- A. 8.21
- B. 9.21Correct
- C. 10.21
- D. 9.81
Explanation. Rise = 74.04 - 64.83 = 9.21 percentage points, using the values in Table 12.1 of the lesson.
Q15
In the simple line graph of India's literacy rate, the scale used on the x-axis is
- A. 1 cm = 1 year
- B. 1 cm = 5 years
- C. 1 cm = 10 yearsCorrect
- D. 1 cm = 10% literacy
Explanation. The literacy rate graph uses an x-axis scale of 1 cm = 10 years and a y-axis scale of 1 cm = 10% literacy.
Q16
Diagrams which represent quantities by bars are also known as
- A. Columnar diagramsCorrect
- B. Volume diagrams
- C. Polygraphs
- D. Isopleths
Explanation. The diagrams which represent quantities by bars are known as bar diagrams, columnar diagrams or bar-graphs. The length of each bar is proportional to the quantity it represents.
Q17
Assertion (A): All the bars of a bar diagram should be placed at intervals of equal distance.
Reason (R): The width of each bar should vary according to the quantity it represents.
- A. Both A and R are true and R explains A
- B. Both A and R are true but R does not explain A
- C. A is true but R is falseCorrect
- D. A is false but R is true
Explanation. The book says bars should be placed at equal intervals, so A is true. It also says the width of all bars should be similar; only the length is proportional to the quantity, so R is false.
Q18
A compound bar diagram is also called a
- A. Multiple bar diagram
- B. Comparative bar diagram
- C. Sub-divided bar diagramCorrect
- D. Percentage bar diagram
Explanation. The four kinds of bar diagram are simple, comparative or multiple, compound or sub-divided, and percentage. So the compound bar diagram is the sub-divided bar diagram.
Q19
For a simple bar diagram, it is advisable to arrange the given data set in
- A. alphabetical order
- B. ascending or descending orderCorrect
- C. the order of collection
- D. random order
Explanation. A simple bar diagram is constructed for an immediate comparison, so the book advises arranging the data set in ascending or descending order before plotting.
Q20
Which diagram is constructed to show the proportion of males and females in the total population of a country over several years?
- A. Simple line graph
- B. Simple bar diagram
- C. Multiple bar diagramCorrect
- D. Pie diagram
Explanation. Multiple bar diagrams represent two or more variables for comparison, such as males and females in the total population, as in Example 12.4 on India's population from 1951 to 2011.
Q21
According to Table 12.3 of the lesson (FAO, 2012), which country was the largest producer of rice?
- A. India
- B. Indonesia
- C. ChinaCorrect
- D. Bangladesh
Explanation. Table 12.3 lists China first with 197221 thousand tonnes, ahead of India with 120620 and Indonesia with 66412 thousand tonnes.
Q22
In a pie diagram, the angles of the sectors subtending at the centre are proportional to
- A. the radius of the circle
- B. the magnitudes of the frequency of the componentsCorrect
- C. the number of components
- D. the length of the bars
Explanation. A circle of 360 degrees is divided into sectors whose angles at the centre are proportional to the magnitudes of the frequency of the components.
Q23
The angle of a component in a pie diagram is obtained by the formula
- A. (Total value ÷ Value of component) × 360
- B. (Value of component ÷ Total value) × 100
- C. (Value of component ÷ Total value) × 360Correct
- D. (Value of component ÷ 360) × 100
Explanation. Step 3 of constructing a pie diagram: angle value = (value of component / total value) x 360, so each component's share is converted into degrees.
Q24
Asia has 46.85% of the area under wheat cultivation in Table 12.5. What angle does Asia's sector make at the centre of the pie diagram?
- A. 46.85 degrees
- B. 93.70 degrees
- C. 168.66 degreesCorrect
- D. 180.00 degrees
Explanation. Angle = (46.85 / 100) x 360 = 168.66 degrees, which the book rounds to 169 degrees for drawing the sector.
Q25
Oceania has 6.25% of the area under wheat cultivation. Using the pie diagram formula, its sector angle is
- A. 6.25 degrees
- B. 22.5 degreesCorrect
- C. 25 degrees
- D. 62.5 degrees
Explanation. Angle = (6.25 / 100) x 360 = 22.5 degrees, as worked out in Example 12.5 of the lesson.
