Introduction to Graphs Class 8 Extra Questions and Answers Free PDF Download
FAQs on CBSE Important Questions for Class 8 Maths Introduction to Graphs - 2025-26
1. What types of graphs are most important to practise for the Class 8 Maths exam from Chapter 13, based on the 2025-26 syllabus?
For the CBSE Class 8 Maths exam, you should focus on four key types of graphs from Chapter 13. Important questions are frequently framed around:
- Line Graphs: These are crucial for showing how data changes over time. Expect questions that require you to plot a line graph from a table of values or interpret a given one.
- Bar Graphs: Used for comparing discrete categories. Questions might ask you to draw a bar graph to represent data like marks in different subjects or production over years.
- Histograms: These are important for representing data in continuous intervals. A common question involves creating a histogram from a frequency distribution table.
- Pie Charts (or Circle Graphs): Used to show parts of a whole. Questions often involve calculating angles for each sector and drawing the chart.
2. What kind of 3-mark or 5-mark important questions can be expected from 'Introduction to Graphs'?
In the Class 8 exams, higher-mark questions from this chapter test your application and interpretation skills. Expect questions such as:
- Plotting a Linear Graph: You may be given a linear equation or a table of (x, y) values and asked to plot the corresponding straight-line graph on a Cartesian plane. This tests your understanding of coordinates and scale.
- Interpreting a Time-Distance Graph: A 5-mark question could present a complex line graph showing a journey and ask multiple sub-questions about speed, distance covered in a specific time, and periods of rest.
- Creating a Histogram: You might be given raw data and asked to first create a grouped frequency distribution table and then draw a histogram from it, which is a multi-step process often worth more marks.
3. What are the key steps to ensure I score full marks when plotting a graph in my exam?
To score full marks on a graph-based question, examiners look for precision and correct labelling. Follow these steps:
- Title: Always give your graph a suitable title that describes what it represents.
- Axes Labelling: Clearly label the x-axis and the y-axis with the quantities they represent (e.g., 'Time in hours', 'Temperature in °C').
- Choosing a Scale: Select a clear and consistent scale for both axes. The scale should be easy to read and large enough to use the graph paper effectively. Mention the scale clearly on the graph (e.g., On x-axis, 1 cm = 5 units).
- Plotting Points: Mark the points with a sharp pencil as small dots and circle them for clarity. Ensure the coordinates are plotted accurately.
- Joining Points: Use a ruler to join the points for a line graph or draw neat bars for a bar graph/histogram.
4. What is the main difference between a bar graph and a histogram? When are they used in exam questions?
This is a common point of confusion and an important concept. The key difference lies in the type of data they represent. A bar graph is used to display discrete, separate categories (e.g., favourite colours, number of students in different classes). There are gaps between the bars to show they are distinct. In contrast, a histogram is used to display continuous data that is grouped into intervals (e.g., height of students in the range 140-145 cm, 145-150 cm, etc.). There are no gaps between the bars in a histogram, indicating the continuous nature of the data.
5. Why is mastering Chapter 13, 'Introduction to Graphs,' considered crucial for success in higher classes like 9 and 10?
Mastering graphs in Class 8 is fundamental because it is a foundational skill for several advanced topics. In Class 9 and 10, this knowledge is directly applied in:
- Coordinate Geometry: The concepts of plotting points (abscissa and ordinate) are the building blocks of this entire unit.
- Linear Equations in Two Variables: You will be required to represent linear equations graphically as straight lines.
- Statistics: You will create more complex graphs like frequency polygons and ogives, which build upon the histogram concept.
- Science (especially Physics): Graphs are essential for representing motion (distance-time and velocity-time graphs) and other scientific relationships.
6. What types of short-answer or MCQ questions are frequently asked from this chapter?
For 1-mark questions, you can expect direct and concept-checking problems. Important types include:
- Identifying the coordinates of a point plotted on a graph.
- Finding the abscissa (x-coordinate) or ordinate (y-coordinate) of a given point.
- A question asking which axis a point like (0, 5) or (3, 0) lies on.
- Simple interpretation from a bar graph, like 'Which category has the highest value?'.
- Determining if a statement about a graph is true or false.
7. How do you decide the correct 'scale' for a graph when the data values are very large or uneven?
Choosing the right scale is a critical thinking skill. First, find the range of your data (highest value - lowest value) for both axes. Then, look at the available space on your graph paper. Divide the range by the number of available grid units to get an idea for the scale. For instance, if your data goes up to 500 and you have 10 cm of space, a scale of 1 cm = 50 units would be appropriate. If the data starts from a large value (e.g., 400), you can use a 'kink' or 'break' on the axis to show that you are skipping the initial numbers, allowing you to use a more detailed scale for the relevant data range.
8. Can a line graph be non-linear? What does a straight line on a graph signify in the context of Chapter 13?
Yes, a line graph can be non-linear. A line graph is simply a graph formed by joining plotted points. If the relationship between the variables is not constant, the resulting graph will be a series of connected line segments with different slopes, forming a 'broken' line. A straight line (a linear graph) is a special case that is very important. It signifies a uniform or constant rate of change between the two variables. For example, in a distance-time graph, a straight line means the object is moving at a constant speed.

















