The virtual image of a plane mirror is the optical representation formed by the reflection of light rays from an object. As stated in the reference, the image formed by a plane mirror is always virtual (meaning that the light rays do not actually come from the image). This means the image appears to be behind the mirror, but the light rays do not converge at that location.
Understanding the Virtual Image
Unlike a real image, which can be projected onto a screen because light rays converge there, a virtual image cannot be projected. Your brain perceives the light rays as if they originated from a point behind the mirror.
Key characteristics of the virtual image formed by a plane mirror, according to the reference, are:
- Virtual: Light rays do not actually meet at the image location.
- Upright: The image is oriented the same way as the object (not inverted).
- Same Shape and Size: The image is identical in shape and dimensions to the object being reflected.
How is a Virtual Image Formed?
When light rays from an object strike the smooth surface of a plane mirror, they reflect off it according to the law of reflection (angle of incidence equals angle of reflection). For a plane mirror, these reflected rays diverge as they leave the mirror.
Our eyes and brain interpret these diverging rays as if they came from a point behind the mirror where they would have converged if they hadn't been reflected. This point behind the mirror is where the virtual image is located.
Properties of a Plane Mirror Image
Let's summarize the properties of the image formed by a plane mirror:
- Type: Virtual
- Orientation: Upright
- Size: Same size as the object
- Location: Appears to be as far behind the mirror as the object is in front.
- Lateral Inversion: The image is laterally inverted, meaning it is flipped left-to-right (e.g., writing appears backward).
Image Characteristics Table
| Characteristic | Description |
|---|---|
| Type | Virtual (Light rays do not meet) |
| Orientation | Upright (Same orientation as object) |
| Size | Same size as the object |
| Distance | Image distance = Object distance (behind mirror) |
| Lateral Inversion | Image is flipped left-to-right |
Practical Examples
You encounter virtual images from plane mirrors every day:
- Bathroom mirror: When you look at yourself, you see a virtual image that appears to be behind the mirror.
- Shop changing rooms: Mirrors create a virtual image of your reflection.
- Periscopes: Use plane mirrors to create virtual images, allowing you to see over obstacles.
Understanding that the image is virtual explains why you can't project your reflection onto a wall using just a plane mirror.
Conclusion
In essence, the virtual image of a plane mirror is the upright, same-sized, and laterally inverted reflection that appears to be located behind the mirror, formed by the divergence of light rays that do not actually converge there.
