An image that can be formed on the screen is known as a real image and the one which cannot be formed on the screen is known as a virtual image. These images are formed when light falls on a mirror from the object and is reflected back by the mirror on the screen. There can be two types of mirror: Curved mirror and plane mirror. If a curved mirror is a part of a sphere then it is known as a spherical mirror. The image formed by a plane mirror is always a virtual image as it cannot be obtained on a screen. The image formed by the spherical mirror can be either real or virtual. Spherical mirrors are of two types:
- Convex mirrors
- Concave mirrors
Definition of Convex Mirror –
Convex mirror refers to a curved mirror in which the reflective surface bulges out towards the source of light. This bulging surface reflects light outwards. Moreover, people will notice that these mirrors form erect and virtual images. Moreover, they are diminished in nature. A convex mirror is also known as a diverging mirror as this mirror diverges light when they strike on its reflecting surface. Virtual, erect, and diminished images are always formed with convex mirrors, irrespective of the distance between the object and the mirror. Apart from other applications, the convex mirror is mostly used as a rearview mirror in vehicles.
Spherical mirrors are the mirrors having curved surfaces that are painted on one of the sides. Spherical mirrors in which inward surfaces are painted are known as convex mirrors while the spherical mirrors in which outward surfaces are painted are known as concave mirrors. Concave mirrors are also known as a converging mirror since the rays converge after falling on the concave mirror while the convex mirrors are known as diverging mirrors as the rays diverge after falling on the convex mirror.
These mirrors are used as rearview mirrors in cars or motorbikes, ATMs, hallways of schools, hospitals, stores, etc., to help the people view, what’s happening behind them.
Definition of Concave Mirror –
A concave mirror is a mirror that has a reflecting surface such that it is recessed inwards. Furthermore, only real and inverted images are produced by concave mirrors. However, these real and inverted images do not form when the object is between pole and focus. Moreover, the concave mirrors produce images in a magnified form. In other words, the objects in this mirror will appear much bigger than they actually are. Its shape is identical to a spoon.
The reflecting surface of a concave mirror bent inward to focus, i.e. away from the light source. When the light is bounded by the curve up to a particular area, they form an image. It can reflect images in two ways:
- When the object is closer to the mirror, the image formed will appear larger and right side up, i.e. a virtual image is formed.
- When the object is farther away to the mirror, the image formed will appear small, and upside down, i.e. a real image is formed.
Hence, it is also known as a converging mirror. When the concave mirror is placed very close to the object, a magnified and virtual image is obtained. But if we increase the distance between the object and the mirror then the size of the image reduces and a real image is formed. So the image formed by the concave mirror can be small or large and it can also be real or virtual.
For instance, the headlight of an automobile is a concave mirror. Similarly, the reflecting telescopes, eyeglasses, torch lights, cameras, lasers, and more all examples of these mirrors. They are also used by dentists, or as shaving mirrors.
Key Differences Between Convex and Concave Mirror –
The difference between convex and concave mirror is explained hereunder:
- The type of spherical mirror whose reflecting surface is bulged outwards, in the sense that its face is opposite to the center of the sphere is known as a convex mirror. A curved mirror whose reflecting surface is bent inwards, i.e. it faces towards the center of the sphere is called a concave mirror.
- The focal point of the convex mirror lies behind the mirror, wherein the case of a concave mirror the focal point lies in front of the mirror.
- Convex mirror is also called as a diverging mirror as the light beam arising from the same source will reflect and diverge. As against, a concave mirror is a converging mirror, as when a parallel light beam falls on the mirror, they reflect and converge at a point.
- The image formed by a convex mirror is a virtual image, while the concave mirror forms a real or virtual image, depending on the position of the object.
- Convex mirrors are used as rear-view mirrors in cars, to enable the driver to see the traffic behind him. On the contrary, concave mirrors are used in torches and vehicle headlights.
When the image is of the same size, we are looking at a plane mirror. Then, if our face looks bigger, we are looking in a concave mirror. Similarly, if our face looks smaller, then it’s a convex mirror. The two mirrors are diametrically opposite to one another and produce different images at different positions.
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