The image formed by a plane mirror possesses several distinct characteristics, making it appear as a reflection of the object behind the mirror surface.
Key Characteristics of Plane Mirror Images
Based on the properties of light reflection from a flat surface, the image produced by a plane mirror is always virtual, erect, the same size as the object, located the same distance behind the mirror as the object is in front, and exhibits lateral inversion.
Let's break down these characteristics:
1. Virtual Image
A virtual image is one that cannot be projected onto a screen. The light rays from the object appear to originate from the image location behind the mirror, but they do not actually converge there. You see a virtual image because your brain extrapolates the diverging reflected rays back to a point where they seem to meet.
- Practical Insight: This is why you can see yourself in a mirror, but you can't capture that image on a piece of paper placed where the image appears to be.
2. Erect Image
An erect image means the image is upright relative to the object. If the object is standing up, the image will also be standing up, not upside down.
- Example: When you look at yourself in a bathroom mirror, your head is at the top of your reflection, just as your head is at the top of your body.
3. Size of the Image
The size of the image formed by a plane mirror is always equal to that of the object. The mirror does not magnify or reduce the image.
- Practical Use: This property is useful in applications where a true-to-size reflection is needed.
4. Distance of the Image
The image formed is as far behind the mirror as the object is in front of it. This means the distance from the object to the mirror is equal to the distance from the mirror to the image.
- Observation: If you walk towards a mirror, your reflection also appears to walk towards the mirror from the other side, covering the same distance.
5. Laterally Inverted
Lateral inversion means that the image is reversed from left to right. While the image is not upside down (erect), the left side of the object appears as the right side of the image, and vice versa.
- Common Example: Looking in a mirror, your right hand corresponds to the left hand of your reflection. Ambulances often have the word "AMBULANCE" written in reverse so that drivers looking in their rearview mirrors see the word correctly.
Summary Table
Here is a concise summary of the characteristics:
| Characteristic | Description |
|---|---|
| Virtual | Cannot be projected onto a screen; light rays do not converge at the image. |
| Erect | Upright relative to the object. |
| Same Size | The height and width of the image match the object. |
| Same Distance | Image is as far behind the mirror as the object is in front. |
| Laterally Inverted | Reversed from left to right. |
These characteristics are fundamental to understanding how plane mirrors work and distinguish them from other types of mirrors like concave or convex mirrors.
Information from the reference source aligns with these points: "Image formed by a plane mirror is always virtual and erect. The size of the image is equal to that of the object. The image formed is as far behind the mirror as the object is in front of it. The image is laterally inverted." Source
