- Virtual: The image is virtual, meaning light rays don't actually come together at the location of the image. It appears to be behind the mirror where light wouldn't physically exist.
- Erect: The image maintains the same orientation as the object. You see yourself upright in a plane mirror.
- Laterally Inverted: The image is flipped left-to-right compared to the object. When you raise your right hand in front of a mirror, the image raises its left hand.
- Same Size: The image has the same size as the object.
- Same Distance: The distance of the image behind the mirror is equal to the distance of the object in front of the mirror.
One common situation where a virtual image is formed is by a plane mirror. When you look at yourself in a mirror, the image you see is a virtual image. The light rays reflecting off you diverge away from the mirror's surface, and when we trace those rays back behind the mirror (which isn't where the light actually goes), they appear to meet at a point where your virtual image is located. This is why you can't project the image from a mirror onto a screen – the light rays aren't actually coming together behind the mirror.
Convergence vs. Divergence of Light:
- Convex lens (converging lens): Bends light rays inward, focusing them to a point (focal point) on the other side. This creates a real or virtual image depending on the object's distance.
- Concave lens (diverging lens): Bends light rays outward, causing them to spread apart. It does not form a real image on its own, but can create a virtual, upright, and diminished image.
Image Formation:
- Convex lens: Can form both real and virtual images.
- Real, inverted image: When the object is placed beyond the focal point.
- Virtual, magnified image: When the object is placed within the focal point.
- Concave lens: Can only form virtual images. These images are always upright and smaller than the object.
- Convex lens: Can form both real and virtual images.
- Concave Mirror: Telescopes
Concave mirrors are used in telescopes because of their ability to collect and focus light. The inward curvature of the mirror reflects incoming light rays towards a single point, concentrating the light and magnifying distant objects. This allows astronomers to observe celestial bodies in greater detail.
- Convex Mirror: Security/Surveillance Mirrors
Convex mirrors, also known as fisheye mirrors, bulge outwards, providing a wider field of view than a flat mirror. This makes them ideal for security and surveillance applications. They are commonly placed at blind corners in stores or hallways to allow security personnel or even shop owners to see a larger area, improving security and reducing blind spots.
Concave Mirror: A concave mirror can form a real, inverted image when the object is placed beyond the focal point. In this scenario, the reflected rays converge to a real point after reflecting off the mirror, creating a sharp image.
Convex Mirror: Convex mirrors typically do not form real images because they cause light rays to diverge. However, there is a special case where a convex mirror can create a real image: when the object is placed very close to the mirror's surface. In this case, the image is formed behind the object, is erect, and is diminished in size.
Concave lenses are diverging lenses, meaning they bend light rays outwards as they pass through the lens. This spreading of light rays never results in a real image converging to a point on the other side. Instead, the image appears to be located behind the lens where the light rays appear to originate – this is a virtual image.
While a concave lens can only create virtual images, these images are always:
- Erect (upright): The image has the same orientation as the object.
- Diminished: The image is smaller than the actual object.
