In geometrical optics, the image formed by a plane mirror has several characteristic properties. The specific type of reversal shown by the image in a plane mirror is known as ______.

Introduction / Context:

Plane mirrors are among the simplest optical devices and appear in many competitive exam questions. Their image properties are standard: the image is virtual, upright, of the same size as the object and laterally inverted. This question focuses specifically on the type of reversal that occurs, checking whether you remember the correct technical term for the left right reversal seen in plane mirrors.

Given Data / Assumptions:

• We are dealing with an ordinary plane mirror, such as a bathroom mirror.
• The object is placed in front of the mirror in air, and standard laws of reflection apply.
• We are interested in how the orientation of the image compares with the object.
• Terms like real, virtual, inverted, enlarged, diminished and lateral inversion are used in their usual school physics sense.

Concept / Approach:

When you stand in front of a plane mirror and raise your right hand, the image appears to raise its left hand. This is called lateral inversion, meaning left right reversal. The top and bottom of the image are in the same orientation as the object, so there is no vertical inversion. Because the reflected rays appear to diverge from a point behind the mirror, the image is virtual rather than real. The size of the image is equal to the size of the object, so it is not enlarged or diminished. Therefore, among the given options, the correct description of the specific reversal produced by a plane mirror is lateral inversion.

Step-by-Step Solution:

Verification / Alternative check:

You can test this effect using text printed on paper. When you hold the text in front of a plane mirror, you see that the letters appear reversed left to right, such that it becomes difficult to read. Ambulances often have the word AMBULANCE written reversed on the front of the vehicle. When a driver ahead looks in the rear view mirror, the lateral inversion of the mirror makes the word appear in the correct orientation, allowing quick recognition. This is a practical demonstration of lateral inversion by a plane mirror.

Why Other Options Are Wrong:

Option A (vertical inversion): Plane mirrors do not flip the image upside down. The head stays at the top and the feet at the bottom.

Option B (a real and inverted image): Images in plane mirrors are virtual and upright, not real and inverted. Real inverted images are produced by concave mirrors in certain positions.

Option D (an enlarged image): The image in a plane mirror is of the same size as the object, so it is neither enlarged nor diminished.

Option E (a diminished image): Similar reasoning applies; the image size equals the object size for plane mirrors.

Common Pitfalls:

Students sometimes confuse the terms inverted and lateral inversion. Inverted usually means upside down relative to the object, while lateral inversion refers to left right reversal. Plane mirrors cause lateral inversion but not upside down inversion. Keeping this distinction clear helps in answering many optics questions correctly and prevents mixing up the properties of plane, concave and convex mirrors.

Final Answer:

The image in a plane mirror shows lateral inversion.