Mirror and water image questions test whether you can apply reflection accurately. A mirror image reflects a figure across a vertical line, while a water image reflects it across a horizontal line. The figure keeps its size and shape, but its position and direction change according to the reflecting line.

1. Mirror image rules

A mirror placed to the right or left of an object creates a left-right reversal. The top and bottom remain unchanged, but every right-side feature moves to the left and every left-side feature moves to the right.

• The distance of each point from the mirror line stays the same.
• Top stays top and bottom stays bottom.
• Left and right are interchanged.
• Letters, arrows, and irregular shapes appear reversed rather than simply rotated.

2. Water image rules

A water image is reflected across a horizontal line. Left and right remain unchanged, while top and bottom interchange. Think of the original figure standing above a calm water surface and its reflection appearing directly below it.

• The distance of each point from the water line stays the same.
• Left stays left and right stays right.
• Top and bottom are interchanged.
• An upward arrow becomes a downward arrow, but it does not swap sides.

3. A reliable solving method

1. Identify whether the reflecting line is vertical (mirror) or horizontal (water).
2. Mark the most asymmetric feature: a dot, arrowhead, curve, or diagonal branch.
3. Move that feature across the reflection line while keeping its distance unchanged.
4. Check the direction of diagonals: a rising diagonal becomes falling in a mirror image, and also flips vertically in a water image.
5. Verify the positions of every distinctive feature before selecting an option.

4. Rotation is not reflection

Rotation turns a figure around a point, whereas reflection flips it across a line. A 180-degree rotation changes both left-right and top-bottom positions. A mirror image changes only left-right; a water image changes only top-bottom.

Common mistakes

• Using a 180-degree rotation for a mirror or water image.
• Reversing left-right for a water image.
• Reversing top-bottom for a mirror image.
• Ignoring a small asymmetric dot, notch, or diagonal line.
• Choosing an option that changes the figure's size or distance from the reflecting line.

Quick revision summary

• Mirror image: vertical reflection; left and right swap.
• Water image: horizontal reflection; top and bottom swap.
• Reflection preserves distance from the reflecting line.
• Track one distinctive feature first, then verify the rest.