Mirror and Water Image for Design Exams: Concepts, Important Questions & Answers

Mirror and Water Image questions are frequently asked in the Design DAT Examinations, like NID (National Institute of Design) and UCEED (Undergraduate Common Entrance Examination for Design) including the entrance examinations conducted by reputed design universities in India. This article will explore concepts like lateral inversion, vertical inversion, visualisation techniques, and symmetrical concepts for the mirror and water image. Once the fundamentals are cleared, these are two great Scoring Areas for any aspirant. Read the complete article for knowledge on how to solve mirror and water image questions.

Difference between mirror and water image

Mirror Image: When an observer looks at an object in a mirror, it is called a mirror image. In this case, the original object has been inverted so that the left side is on the right side and the right side is on the left.

Original Image Mirror Image Original Image Mirror Image

Points to Note

1. When we talk about mirror images, we consider the flat version of the mirror unless it is mentioned in the question.

2. The size of the object reflected never changes. Neither does it become bigger or smaller in the mirror image.

3. The object reflected as seen in glass is the same without any shift or divergence from the original form.

Sample Question

For the image on the left, find the correct mirror image using the given options.

Solution Approach:

Step 01: For most DAT examinations, never settle for the right option; rather, it is advised to adopt the “Elimination” approach, rejecting the options that are fundamentally wrong to reach the right option.

Step 02: The diagonal line is wrongly aligned in option C, eliminating option C. In option B, the indicated lines are parallel but not in question; the mentioned lines are not parallel, thus eliminating option B, as shown in the figure.

Step 03: Now, comparing options A & D itself , we see the inner square and the lines in the pattern inside the smaller square in option D are the same as the question which is not possible. Thus, the only option is left, and on cross-checking, we find that option (A) is correct.

Practise Questions: Mirror Image

Question 01: For a given image(alphanumeric code), find the correct option for the mirror image formed.

Water Image: When an observer looks at an object in water, the inverted form visible for the object is called a water image. Appearing as a vertically inverted version of the object, it shows symmetry along the horizontal axis (waterline)

Note: When we talk about water images, we consider the stand-still state of the water with no disturbance or discontinuity on the water surface.

Key points to understand

1. Reflection Symmetry: Water images show a reflection of the object, similar to a mirror placed horizontally at the waterline.

2. Vertical Inversion: The reflection is an inverted version of the object along the horizontal axis (upside down).

3. Perspective and Depth: Objects closer to the water surface appear larger and more detailed in their reflection, while those farther away appear smaller and less detailed.

How to identify the Water Image?

1. Check if the object appears flipped upside down along the horizontal axis (waterline). For example, "2" should resemble a reversed "S" below the waterline.
   
   
   
   

2. Ensure that the original object and its reflection are symmetrical relative to the waterline. The distance from any point on the object to the waterline should be equal to the distance from the corresponding point on the reflection to the waterline.

3. Verify that the reflected image maintains the exact proportions and alignment as the original object. For example, if the original object is a triangle pointing upwards, the reflection should be a triangle pointing downwards, maintaining the same base width and height.

Sample Question:

Choose the correct water image of the question figure from the given answer figures (assume that water is along XY)

Approach to Solution:

Step 01: We'll start by eliminating the option/s which are different from the question. Just like option (3), which comprises an element-middle black triangle, which is different from the middle triangle present in question and option (4), in which the image is as it is, only the black-shaded region is mirrored. Also, the whole part is not inverted.

Step 02: This leaves us with two options (1) and (2). We will compare the shaded black region with the question because the rest is the same. On comparing, we can see that the black shaded region is mirrored in option (1), it should be on the same side only just below.

Step 03: That can be seen in option (2). The correct answer is option (2).

Practice Questions:Water Image

Question 01: Choose the correct option that resembles the given combination's water image.

Question 02: Choose the correct water image of the question figure from the given answer figures (assume that water is along XY)