Introduction
A spherical mirror is a mirror that has the shape of a piece carved out of a sphere.
A spherical mirror is categorised into two forms, namely: concave and convex. On this page, we'll learn about the following:
Type of spherical Mirrors
Application: usage, Examples
Derivations for a mirror formula with a ray diagram
Mirror images with their attributes: R, C, f, P, and Principal axis
The surfaces of most curved mirrors are shaped as spheres, although optical devices can sometimes use other shapes. For example, a plane mirror is a mirror whose reflecting surface is flat, and if the reflecting surface is curved, the mirror is called a curved mirror.
Types of a spherical mirror
There are two types of curved mirrors;
Concave mirror: Outer surface: silvery polished, inner surface: reflective
Convex mirror: Outer surface: Reflective, Inner surface: Polished Light reflected by convex and concave mirrors
Take a spoon for an example; there are two such reflecting surfaces on a spoon. These two mirrors are called spherical mirrors. The reflecting surface on both sides look like a part of a sphere, hence the name. These two are further given a notable name. The mirror that has its reflecting surface curved inwards is called a concave mirror, and the mirror that has its reflecting surface curved outwards is called a convex mirror.
Applications
Concave Mirrors are used as reflectors and converging of light. It is used as a makeup and dentists mirror, headlights for a motor vehicle etc. Convex Mirror is used in security monitors in ATMs, hospitals, hotels, schools etc. It is also used as side-view mirrors in cars.
Concave Mirror
Reflectors, Converging of light, Solar cooker, motor vehicle headlight, shaving, and makeup mirror, microscope, Telescope, Satellite dishes, dentist's mirrors.
Convex Mirror
It is used in security monitors, Side-view mirrors in cars, Security mirrors in ATMs, in buildings such as hotels, hospitals, stores, schools, etc. Key points: Consider a ray image of a Concave Mirror.
Derivation of Mirror Formula
In a mirror, the place that is the centre of the reflecting surface is called a pole. It is represented with a point P. There is also a centre in the sphere called the centre of the curvature, and the radius will be called the radius of the curvature. The line joined from the pole to the centre of the curvature is called the principal axis. The midpoint of the line segment joining the pole P and the centre of curvature C is called the focal point. It's denoted by the letter F.
f = focal length
a = The distance of the object from the pole of the mirror.
b = The distance of the image formed from the mirror.
A few patterns that are essential to understand before deriving the equation are:
Pole "P" is the place from where all distances are measured.
Distances measured in the light incidence direction are considered positive, and those taken from the opposite direction are deemed negative.
The positive and negative points can be determined by the height, if they are above the principal axis, they are supposed to be positive and when the height is lower than the principal axis are negative.
The positive and the negative image distance can be determined by the ray diagram.
FAQs on Spherical Mirrors
1. What are the best ways to understand the topic of spherical mirrors?
The best way to understand the topic of spherical mirrors is to get a general idea about the physics behind them. Spherical mirrors are curved objects and are made from a sphere. The students’ understanding of the curved surfaces, whether it is concave or convex, determines the knowledge about their applications and types. Vedantu has in-depth notes about spherical mirrors, their usage, properties and derivations required to make spherical mirrors and their subtopics easy to understand by the students.
2. Are diagrams helpful in learning about spherical mirrors?
Yes, it is highly advisable to use diagrams to study since the concept of mirrors can be understood easily with images rather than with just the text. This is because the images are instilled in the mind with a concept, whereas this is not as quickly when happening with text. To learn about spherical mirrors with ease, students can check out the easiest and flashy content to help them study better from the official website of Vedantu. The content is in the form of PDFs, which are free of cost.
3. What is an example of a mirror reflection?
An example of a concave mirror can be the Sun as the only parallel rays of light to be incident on the mirror, and the rays of light from the Sun can be considered to be almost parallel. Being a sphere, the Sun emits light radially outwards; that is, rays of light travel outwards along the radius, but we know that the Sun is at a considerable distance away from the earth. Hence the rays from the Sun coming towards the surface of the earth are parallel, so our object, which is the Sun, is present at infinity and is emitting parallel rays of light.
4. What are concave and convex mirrors?
Mirrors in which the curved reflecting surface forms a part of a sphere are called spherical mirrors. Spherical mirrors can be of two types: one in which the reflecting surface is curved inwards, they are called concave mirrors and the others in which the reflecting surface is curved outwards that are called convex mirrors. A concave mirror is a little more than just a midpoint; It is also a point where all the rays of light parallel to each other as well as to the principal axis converge after reflection.
5. What are the essential terms to remember about spherical mirrors?
Centre of curvature is the term for the hollow sphere of the glass of which the mirror is a part. The centre of the spherical mirror is nothing but the pole. The principal axis is the straight path or line passing through the curvature and the pole. The aperture of the mirror is the portion of the mirror where the reflection of light takes place. After reflection, all of the light rays converge on the principal axis, where the focal point is located. Focal length is the distance between the pole and the principal focus.
