Concave and Convex Mirror

Concave and Convex Mirror: A mirror is a surface that nearly always reflects the light that strikes it. Mirrors are divided into two: Plane mirrors and spherical mirrors. As the name suggests, plane mirrors have a plain, polished surface, while spherical mirrors are curved reflecting surfaces. Spherical mirrors are further divided into Convex and Concave mirrors based on their curves. However, to distinguish between Concave and Convex Mirror, it is essential to understand what they are and how they differ. To put it simply, mirrors with a reflecting surface that bulges outwards are convex mirrors, whereas concave mirrors have a reflecting surface that bulges inwards.

In this article, we will discuss more Concave mirrors and Convex mirrors, how they are formed, the uses of convex mirrors and concave mirrors, etc. Read this article to learn more.

Concave and Convex Mirror: An Overview

What are mirrors? This is a question that students often ask. A mirror can be defined as a smooth and highly polished reflecting surface. A mirror does not allow the passage of light. Any light ray that strikes a mirror bounces off, thus producing a reflection. Now, you might be thinking about how image formation in a convex and spherical mirror happens then. Let us learn about both with the help of diagrams and tables.

Types of Mirror: Plane and Spherical

If the object is placed in front of the mirror, it bounces off the light and produces either the real image or a virtual image of the object. When the light rays intersect, then it creates a real image. Virtual image forms due to the apparent divergence of light rays from a point. A plane mirror always creates the virtual image, while the spherical mirror forms both virtual and real images.

Plane Mirror

The most common mirrors are flat in shape and called ‘plane mirrors’. Plane mirrors are built by putting a thin layer of silver nitrate or aluminium behind a flat piece of glass. In a plane mirror, when a light ray strikes, the incidence angle equals the reflection angle.

Students can refer to the diagram below to get a better understanding of the same.

Spherical Mirror

The spherical mirror forms the virtual or real image because spherical mirrors have a consistent curve and constant radius of the curvature. The basis of the surface painting of the spherical mirror, there are two types, concave and convex mirrors.

1. Concave Mirror: When the outer surface of the spherical mirror is painted, concave mirrors are formed.
   
2. Convex Mirror: When the inner surface of the spherical mirror is painted, convex mirrors are formed.

Terms Used in Spherical Image

The list of terms used in the concave and convex mirror diagram is given below.

Concave Mirror

When the inner surface of a spherical mirror is reflected and the outer surface is painted, it is called a convex mirror.

Characteristics of Concave Mirror

The characteristics of a concave mirror and concave mirror image are given below.

• Concave mirrors are also known as converging mirrors because they converge light to one prime focus point.
• A magnified or virtual image is formed when the object is placed very close to the concave mirror.
• When the object is placed far from the mirror, then the size of the image reduces, which forms a real image.

Image Formation by Concave Mirror

Based on the distance between the mirror and the object, various images are formed in a concave mirror. The placement of the object can be of the following types.

• When the object is placed at infinite
• When the object is placed beyond the centre of the curvature
• When the object is precisely placed at the curvature
• When the object is placed between the principal focus and the centre of the curvature
• When the object is placed at the principal focus
• When the object is placed between the pole and the principal focus

Concave Mirror Diagram

The ray diagram of concave mirrors based on the object placement stated above is given below.

Summary of Concave Mirror Ray Diagram

Uses of Concave Mirror

The uses of the concave mirrors and concave mirror examples are given below.

• Concave mirrors are primarily used in torches, vehicle headlights, flashlights, and searchlights.
• Shaving mirrors are also made up of concave mirrors to see the larger image of the face.
• Dentists also use concave mirrors to see the larger image of the patient’s teeth.
• To produce heat in solar furnaces, large concave mirrors are used to concentrate sunlight.
• Concave mirrors are used in reflecting telescopes to catch the reflections of distant celestial objects.

Convex Mirror

When the outer surface of a spherical mirror is reflected and the inner surface is painted, it is called a convex mirror.

Properties of Convex Mirror

The characteristics of convex mirrors and convex mirrors example are given below.

• Convex mirrors are also known as diverging mirrors since they reflect light outwards.
• They do not converge light to one prime focus point.
• Irrespective of the distance between the object and mirror, the convex mirror always forms virtual, diminished, and erect images.
• A convex mirror is also known as a diverging mirror since the incident ray of light originating from the same point diverges off the mirror surface.

Image Formation by Convex Mirror

The image formed by a convex mirror is always virtual and erect. The types of object placement in a convex mirror are given below.

• When an object is placed at infinity
• When an object is placed between the pole and infinity

Convex Mirror Ray Diagram

The image formed by the convex mirror based on the image placement stated above is given below.

Summary of Convex Mirror Ray Diagram

The output image based on the distance between object and mirror is given below.

Uses of Convex Mirror

The uses of the convex mirror are given below.

• Convex mirrors are widely used as rear-view (wings) mirrors in vehicles.
• Convex mirrors are usually used on the sides of vehicles, enabling the driver to see the traffic or vehicles coming behind the driver.
• We can see a much larger area or object in a convex mirror, which is impossible in a plane mirror.

What Is the Difference Between a Concave and Convex Mirror?

The significant differences between concave and convex mirrors in physics are tabulated below.

FAQs on Concave and Convex Mirrors