The image of an object is the visual reconstruction when placed in front of a mirror or self-reflecting surface. The image is formed when light propagating from a source reflects the object and casts its reflected visual on a surface or a mirror. It is to be noted that certain reflective laws are responsible for the formation of the image.
The meeting of the light rays from the source creates the reflected or refracted image. These are also known as real and virtual images in physics terminology. We shall further discuss the comparison of real images and virtual images with their application as we progress. For now, let us dive deep into this subject and discuss with examples to have a clear understanding.
What do you mean by Real Images?
Real images are the type of images formed due to the convergence of light rays from a source towards a point reflected or refracted by a surface or mirror. These images are formed at the point where the interaction of the lights with each other takes place. They are always inverted in nature and are visible on the screen or the surface.
Let us assume that an object is placed in front of a mirror (concave). And a light source hits the object and gets reflected towards the surface of the mirror. Similarly, when multiple light sources hit the object and reflect from the mirror, the image gets reflected.
Let us again assume that an object is placed in front of a concave mirror or a lens. Also, let us suppose that the light gets reflected from the object at observation and touches the concave mirror surface. Also, when multiple light sources touch the concave mirror, these rays touches at one point in front of the mirror after getting reflected from the mirror.
It follows certain laws of reflection from physics, and thus the image is formed. The light rays get diverse from the focus area and move further from the focus point.
What do you mean by Virtual Images?
Virtual Images are the type of images that appears to be formed behind a mirror or a lens. The light rays from the object disperse after reflecting or getting refracted from the mirror’s surface or the lens. This appears like the lights rays are getting reflected from the mirror and look like the image diverging behind the lens or the concave mirror. According to the viewer, the image is formed behind the mirror.
Although, this is not true and is the exact reason why virtual images are not seen on the mirror screen. For instance, the image formed in front of plane mirrors is an example of this type of virtual image. These images have definite shapes and structures similar to the object and can be easily viewed by any kind of optical instrument or even the naked eye.
Differences Between Virtual and Real Image?
Some of the key differences between real and virtual images are listed below –
- Real Images have an inverted image due to their nature, while virtual images are the opposite, i.e. the images are erect.
- In general principle, concave mirrors and lenses produce real images, while virtual images are formed over plane mirrors, convex mirrors, etc.
- The images formed after converging of light sources at a focal point is a real image. At the same time, virtual images result from reflection or the refraction of light after getting a diversion of light rays.
- Real images can be located on a screen, whereas virtual images do not appear on the screen surface.
- Real images are perceived to be formed in front of the mirror surface, while virtual images appear to be formed behind the mirror surface.
- Converging lenses produces real images, while diverging lenses or medium produces virtual images.
Formation of Real Image
As discussed above, a real image is formed by converging rays towards the focal point, while a virtual image is formed after the divergence of light rays on the focal point. We can also interpret that a picture is located on the convergence plane of the light rays from a source object.
Some of the examples of real images are given below –
- The image formed on a movie theatre screen is a real image.
- The image formed on the reel of a camera is a real image.
- The visual image formed on the retina of our human eyes is a real image.
- The images that we see on telescopes, microscopes are also examples of real images.
Virtual Image Formation
As we have already learned before, a virtual image is formed when diverging light rays extend to the focal point where the image is formed. This signifies that a virtual image can be deduced by tracing the light rays that emerge from the optical lens or a mirror toward the back of the mirror or lens.
While representing virtual images, you must have seen the virtual rays represented by dotted lines. A diverging lens like that of a convex mirror produces a virtual image. Such a type of image is formed with reduced size and due to which a bigger scope of the object can be seen on the mirror surface.
In general, no light rays reach the backside of the mirror or the convex lens. Therefore, the viewer perceives the image to be formed away from the mirror, where the light rays appear to be diverse.
Moreover, it is observed that virtual images are not imaginary in nature. These images also possess definite structure, shape and sizes, which can be seen by our human eye or any other optical instrument used by opticians.
Some of the examples of virtual images are listed below –
- The side mirrors of the vehicle use convex mirrors, which shows near objects approaching the vehicle.
- The image produced by a plane mirror is another example of a virtual image.
As we have studied, these two types of images, real and virtual, are created by light rays by the scientific processes of reflection, diffraction, or refraction. One simple and basic difference that can help us identify amongst the two is based on their formation. Real images are formed on a projector screen, while virtual images are formed on the mirror. It is beneficial for students to understand the basics of optic physics because of its wide range of applications in our daily lives.