Mirror Image & Water Image for the Assam Police Constable (AB & UB) Exam
Mirror Image and Water Image is a non-verbal reasoning topic of the SLPRB Assam Police Constable (AB & UB) examination in which a figure, a letter, a number or a word is given and the candidate must find how it will look in a mirror placed on the side or in water below it. The topic tests spatial imagination, that is the ability to picture a figure turned about a line. No general knowledge and no language skill are needed; the whole question rests on a few simple rules. A candidate who remembers which parts change and which stay the same almost never makes a mistake. This page explains the rules of mirroring and water reflection, the worked examples, the shortcuts and the traps that cost marks. The material follows the standard reasoning reference books used for Assam recruitment examinations and is reviewed before it is published.
What the Topic Means
A mirror image is the figure as seen in a mirror placed at the side, usually at the right or the left. In such an image the left and the right are interchanged while the top and the bottom stay the same. A water image is the figure as seen in water below it; here the top and the bottom are interchanged while the left and the right stay the same. The candidate must therefore decide the line about which the reflection takes place and then reverse only the direction that the reflection reverses.
Rules for Mirror Image
- A mirror on the right or the left interchanges the left and the right of the figure.
- The top and the bottom remain unchanged in a side mirror image.
- A vertical mirror produces a horizontal reversal, so the figure is turned left to right.
- When a mirror is placed below or above, the effect is the same as a water image.
- Small details such as the direction of a curve or a tail are also reversed.
Rules for Water Image
- A water image interchanges the top and the bottom of the figure.
- The left and the right remain unchanged in a water image.
- A water image is the same as a mirror placed below the figure.
- The reflection of a letter is taken about a horizontal line.
- Shading above a line moves below the line in the water image.
Letters That Change and Letters That Stay
In a mirror image, the letters that are symmetrical about a vertical line, such as A, H, I, M, O, T, U, V, W, X and Y, look the same, while the others change. In a water image, the letters that are symmetrical about a horizontal line, such as B, C, D, E, H, I, K, O and X, look the same, while the others change. A candidate who knows these two small sets can answer many questions by inspection alone.
A Step by Step Method
- Decide whether the question asks for a mirror image or a water image.
- Decide the line of reflection: a vertical line for a side mirror, a horizontal line for water.
- Reverse only the direction that the reflection reverses, and keep the other direction the same.
- Check each letter, number or part of the figure one by one.
- Compare the result with the options and reject any option that has reversed the wrong direction.
- Confirm by imagining the figure turned about the line once more.
Worked Examples
Example one: the mirror image of the letter b is d, because the left and the right are interchanged. Example two: the water image of the letter b is p, because the top and the bottom are interchanged. Example three: the mirror image of the word AXE is EXA, with the letters placed in the reverse order and each letter mirrored. Example four: the water image of the numeral six is the numeral nine, because the top and the bottom are interchanged. Example five: the mirror image of a clock showing three o'clock shows nine o'clock.
How This Topic Appears in the Examination
The topic usually appears as two to four objective questions of one mark each. The common forms are to find the mirror image of a letter, a number or a word, to find the water image of the same, to find the reflection of a figure about a given line, and to identify the correct mirror or water image from four close options.
Shortcuts and Speed Methods
- Remember the two sets of symmetrical letters for mirror and for water images.
- In a mirror image, read the word from right to left; in a water image, turn it upside down.
- Check only the changed part of the figure and not the whole figure.
- Reject options that have reversed the wrong direction.
- Use a small sketch on paper when the figure is complicated.
Common Mistakes to Avoid
- Turning the figure through half a circle instead of reflecting it.
- Interchanging the left and the right when the question asks for a water image.
- Forgetting to reverse the order of the letters in a mirrored word.
- Keeping a letter the same when it is not symmetrical about the line of reflection.
- Ignoring small details such as a dot, a tail or the direction of a curve.
Preparation Plan
- Learn the symmetrical letters for the mirror and for the water image.
- Practise twenty reflection questions a day, sketching each figure.
- Separate the practice of mirror images and water images.
- Time yourself so that each question takes less than a minute.
- Revise the rules and the letter sets once a week.
More Practice Questions
- The mirror image of p is q.
- The water image of M is W.
- The mirror image of the word MOM is MOM, because every letter is vertically symmetrical.
- The water image of the number 2 is a shape with the curve at the bottom.
- The mirror image of the time 4:30 shows 7:30.
Quick Revision Checklist
- Mirror image reverses left and right; water image reverses top and bottom.
- Vertical line of reflection for a side mirror, horizontal line for water.
- Reverse the order of letters in a mirrored word.
- Remember the symmetrical letters of both types.
- Check every small detail in the figure.
Frequently Asked Questions
What is a mirror image?
A mirror image is the figure as seen in a side mirror, in which the left and the right are interchanged while the top and the bottom remain the same.
What is a water image?
A water image is the figure as seen in water below it, in which the top and the bottom are interchanged while the left and the right remain the same.
Which letters stay the same in a mirror?
The letters that are symmetrical about a vertical line, such as A, H, I, M, O, T, U, V, W, X and Y, look the same in a mirror image.
How is a mirrored word read?
In a mirror image the order of the letters is reversed as well as each letter being reflected, so the word AXE appears as EXA.
Is mirror and water image scoring in Assam Police?
Yes. Each question is solved by applying two or three fixed rules, so it is a reliable place to gain marks in the reasoning paper.