Under the domain of optics, image is referred to the collection of focus points of numerous light rays that emerge from a source or object. The characteristics of images play a vital role in the study of optics and light sources. Images can be further classified into two main types – real images and virtual images.
Real Image vs Virtual Image
The main difference between a real image and a virtual image is that a real image is established by light rays which are converging while a virtual image is established by light rays which are diverging. The light rays which produce real images intersect while the light rays which produce virtual images are considered or imagined to be intersecting.
The real image forms when the light rays meet at a point after refraction or reflection. The meeting point of the light rays is known as the point of intersection. The nature of a real image is always inverted. The real image is depicted by rays of light which are full and solid lines.
On the other hand Virtual image forms when the light rays seem or appear to meet (imaginary). The light rays are usually extended to a point to form the image point. The nature of the virtual image is always upright.
Comparison Table Between Real Image and Virtual Image
| Parameters of Comparison | Real Image | Virtual Image |
| Definition | Real image is formed by converging rays at a focus point or a collection of focus points | Virtual image is formed by diverging rays at a focus point or a collection of focus points |
| Intersection of light rays | Real image is obtained due to actual intersection of light rays | Virtual image is obtained due to imaginary intersection of light rays |
| Nature of image | Real image is always inverted | Virtual image is always upright |
| Position of image | Real image forms on the different side of the object | Virtual image forms on one and the same side with respect to the object |
| Type of rays | Real image is formed due to light rays which are converging at a point | Virtual images are formed due to light rays which appear to be diverging from a point |
What is Real Image?
The real image is formed by light rays that are converging at a focus point or a collection of focus points. The location of the real image is in the plane of convergence that typically begins from an object. Common examples of a real image are images produced on the retina of the eyeball, the image on the cinema screen, the image on the detector in the rear of a camera, and various other such examples.
In physics, the real image is depicted by rays of light which are full and solid lines. The image can only form where these rays converge. Converging lenses and concave mirrors are commonly used to obtain real images. The real image can be inverted if the object is placed far away from the focal point of the lens or the mirror.
The inspection of real images is done by a lens system or second lens. such a mechanism is followed in light microscopes, telescopes, and binoculars. The objective lens can collect the light from the object within the Optical instrument and produce a real image. In the system of lenses or second lenses, the eyepiece projects onto the retina of the eye. The second real image that is formed, is projected through the system.
The light rays intersect and bisect each other to form a real image. The image is such that it can be obtained on a screen. Such a mechanism is followed in projectors. The image can never be upright.
What is Virtual Image?
The virtual image is formed and established by light rays which appear to be diverging at a focus point or a collection of focus points. The location where the virtual image forms is usually in the plane of divergence. The extensions of diverging rays which are received backward can form the type of image. The most common and popular example of a virtual image is the reflection that is formed and achieved in the mirror.
In physics, a virtual image is depicted by rays of light which are dotted lines. The light rays in virtual image seem to be behind the mirror as a source, in a plane mirror. The image formed is of the same size as that of the object. The image is positioned behind the plane mirror.
In a convex mirror or diverging lens, The image formed is of smaller size than that of the object. That tracing back of the light rays to the source from where they seem to appear can provide the location of the virtual image. The formation of the image is usually on one and the same side of the object.
It is not possible to project virtual images on the screen since the rays never converge or intersect. The light rays are considered or imagined to be converging at some point behind the lens. A virtual image can be obtained on a plane mirror or a convex mirror. The image formed in upright in nature. The light rays seem or appear to diverge.
Main Differences Between Real Image and Virtual Image
- The light rays producing real images converge while the light rays producing virtual images appear to diverge.
- Real image can be obtained on a screen while a virtual image cannot be obtained on a screen.
- In diagrams, the real image is formed by full and solid light rays while the virtual image is formed by dotted light rays.
- Real images are produced on a concave mirror or converging lens while virtual images are produced on a convex mirror or diverging lens.
- The nature of the real image is inverted while the nature of the virtual image is erect.
Conclusion
The nature and characteristics of image play a crucial role in the study of optics. It determines the distance of the source as well as the distance where the result could be produced. In physics, images are further classified into two main types that are real images and virtual images.
Both types of images are different from each other. Both have different characteristics, features, sources, applications, and other distinct differences. Both the images are obtained by different types of lenses or mirrors. Knowledge about both types of images can provide insights into the optics subject.
References
- https://onlinelibrary.wiley.com/doi/abs/10.4218/etrij.05.0104.0194
- https://www.osapublishing.org/abstract.cfm?uri=ol-28-16-1421