Introduction
A mirror image is the reflection of an object as seen in a mirror. In this topic, we study how numbers, English alphabets, and various geometric figures appear when placed in front of a vertical mirror. The fundamental principle is that the left side of the object becomes the right side in the reflection, while the top and bottom remain unchanged. Understanding this lateral inversion is key to solving intelligence tests for Grade 7 students.
Explanation Step by Step
Mirror images work on the principle of lateral inversion. Imagine a vertical line representing the mirror. If a point is 2 cm away from the mirror on the left, its reflection will be exactly 2 cm away on the right.
Sub-topics
Mirror Image of Letters and Numbers
Some letters like 'A', 'H', 'I', 'M', 'O', 'T', 'U', 'V', 'W', 'X', 'Y' look the same in the mirror because they are symmetrical. Others, like 'B', 'P', and 'S', change completely.
Examples
Example 1: Word 'RED'
Tricks and Shortcuts
To find the answer quickly, draw the figure on a piece of paper with dark ink. Turn the paper over and look at it from the back against the light. The image you see is the mirror image!
Common Mistakes
Students often confuse mirror images with water images. Remember: in a mirror image, only Left-to-Right changes. In a water image, Top-to-Bottom changes.
Practice Questions
Easy Questions
- What is the mirror image of the number 8?
- Which of these letters remains the same in a mirror: F, G, or M?
- Find the mirror image of the letter 'P'.
Medium Questions
- If the time in a clock is 3:00, what will it look like in a mirror?
- What is the mirror image of the word "BOOK"?
- Identify the mirror image of a right-angled triangle with the 90-degree angle on the bottom left.
Hard Questions
- Find the mirror image of the alphanumeric string: "45B6".
- If a clock shows 9:20, what is the actual time reflected in the mirror?
- Identify the mirror image of a complex figure containing an arrow pointing North-East and a dot at the bottom right.
Revision Summary
Mirror images involve lateral inversion. Left and Right swap places. Vertical position remains constant. Practice with symmetrical and non-symmetrical shapes to master this concept.
