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In the realm of physics, there exist two primary kinds of spherical mirrors: Concave Mirrors and Convex Mirrors. Spherical mirrors are essentially mirrors with curved surfaces, forming part of a hollow glass sphere, distinct from flat mirrors.
A Concave Mirror curves inward on its reflecting surface, earning it the nickname ‘Converging Mirror.’ Conversely, a Convex Mirror features an outwardly curved reflective surface and is referred to as a ‘Diverging Mirror.’
These two mirror types find wide-ranging applications in our daily lives. The key distinction between them lies in how they handle light: Concave mirrors converge light rays to a single point, while Convex mirrors disperse light rays from a central point.
What is a Mirror?
A mirror is like a shiny surface that reflects light and makes pictures. These pictures can be either real or not real.
The thing you’re looking at makes the light bounce, and the pictures are made by the bouncing light.
We can group these pictures into two categories: real and not real. Real ones happen when the light bounces together, and not real ones happen when the light spreads out.
Imagine a flat, smooth mirror – like the ones you find on walls. It always makes not real pictures. These not real pictures are always the same as the thing you’re looking at, and they stand upright.
Now, think about a different kind of mirror, a spherical mirror. This mirror is curved, like a piece of a glass ball.
What are Spherical Mirrors?
Spherical mirrors are mirrors shaped like parts of a round ball. On one side, they have a silvery coating, and on the other side, there’s a polished surface that reflects light. These mirrors create two kinds of images: real and virtual. There are mainly two types of spherical mirrors: concave and convex. You’ll find these mirrors in many everyday items where they’re used for reflecting light.
What are Concave Mirrors?
A concave mirror is a special kind of mirror where the inside surface reflects light. People also call it a “converging mirror” because it makes parallel light rays come together at a point known as the focal point. If you look at its shape, it resembles a spoon.
The following are the properties of concave mirrors:
- Concave mirrors work by causing light to come together at a specific point on their surface, then bouncing back.
- When a concave mirror is positioned very close to an object, it produces an enlarged, upright, and virtual image.
- If the object is situated farther away from the mirror, the resulting image is smaller and flips to become a real and inverted one.
- Concave mirrors have the flexibility to create images that are either tiny or large, and they can be either real or virtual.
What are Convex Mirrors?
A convex mirror is a type of curved mirror with an outward-bending surface. They’re often called diverging mirrors. With convex mirrors, when light hits them, it bounces off in a way that spreads apart from where it started.
Convex mirrors have the following characteristics:
- Pictures produced by convex mirrors appear upright, smaller, and concentrate on the subject.
- These mirrors are referred to as diverging mirrors because the light that bounces off them scatters in various directions.
- They find practical use as rear-view mirrors since they can spread out light rays and create virtual images.
Difference between Concave and Convex Mirror
There are two different kinds of spherical mirrors: concave and convex. A concave mirror brings light rays together, while a convex mirror spreads them apart. In essence, the main difference between these mirrors is as follows:
| Difference between Concave and Convex Mirror | ||
| Aspect | Concave Mirror | Convex Mirror |
| Meaning | A concave mirror has a reflecting curved surface bent inwards, facing the center of the sphere. | A convex mirror has a reflecting surface curved outwards. |
| Alternate Name | It is also known as a Converging Mirror. | It is also known as a Diverging Mirror. |
| Shape | Concave Mirrors have a curved inward shape. | Convex Mirrors have a curved outward shape. |
| Structure | The mirror coating of the concave mirror is on the outer side of the spherical surface. | The mirror coating of a convex mirror is on the inner side of the spherical surface. |
| Centre of Curvature and Reflecting Surface | The center of curvature and the reflecting surface fall on the same side of the mirror. | The center of curvature and the reflecting surface fall on the opposite side of the mirror. |
| Focus | The focus lies in front of the mirror, and the focal length is negative. | The focus lies behind the mirror, and the focal length is positive. |
| Properties of Image | The image formed by a concave mirror can be real, inverted, and enlarged (except when the object is between the mirror and its focus, where the image is virtual, erect, and enlarged). | The image formed by a convex mirror is virtual, erect, and usually smaller. |
| Image Projection | Images produced by concave mirrors can be projected on a screen since they are real. | Images produced by convex mirrors cannot be projected on a screen as they are virtual. |
| Usage | Concave mirrors are used in reflecting telescopes, shaving mirrors, torchlights, etc., as they provide a magnified image of objects. | Convex mirrors are used as side-view or rearview mirrors in vehicles to cover a wider area of view. |
Image Formation By Concave and Convex Mirror
Spherical mirrors create images when they interact with light. Here are some simple rules for how light behaves with concave and convex mirrors:
- If a ray hits the mirror’s center (called the pole), it bounces back at the same angle.
- When a ray runs parallel to the mirror’s main line (principal axis) and hits a concave or convex mirror, it reflects through the focus point.
- If a ray passes through the focus and strikes a concave or convex mirror, it reflects parallel to the principal axis.
- A ray that goes through the center of curvature will bounce back along its original path.
Also Read- What is The Real Image? Real Image All Explanation Available
Image Formation By Concave mirror
Concave mirrors create images in a specific way, and here’s a simple summary:
| Image Formation By Concave mirror | ||
| Position of the Object | Position of Image Formation | Nature and Size of Image |
| Infinity | At the Focus (F) | Real and inverted image; smaller than the Object. |
| Behind the Center of Curvature | Between the Center of Curvature and Focus | Real image; smaller than Object |
| At the Center of Curvature and Focus | At the Center of Curvature | Real image; same size as the Object. |
| In between the Center of Curvature and Focus | Behind the Center of Curvature | Real image; larger than the Object. |
| At Focus | At Infinity | Real image; much larger than the Object. |
| In between Focus and Pole | – | Virtual and erect image; larger than the Object. |
Image Formation By Convex mirror
Formation of images with convex mirrors goes the following:
| Image Formation By Convex mirror | ||
| Position of Object | Position of Image | Nature and Size of Image |
| At Infinity | At the Focus F, behind the Mirror | Virtual and Erect; Highly diminished |
| Between Infinity and the Pole | Between P and F, behind the Mirror | Virtual and Erect; Diminished |
Concave vs Convex Mirror FAQs
What is the main difference between concave and convex mirrors?
Concave mirrors have a curved surface that bends inwards, while convex mirrors have a surface that curves outwards.
Are there other names for concave and convex mirrors?
Yes, concave mirrors are often referred to as Converging Mirrors, and convex mirrors are called Diverging Mirrors.
How do concave mirrors and convex mirrors affect the behavior of light?
Concave mirrors converge light rays to a single point, while convex mirrors disperse light rays from a central point.
Where are concave and convex mirrors commonly used in our daily lives?
Concave mirrors are used in reflecting telescopes, shaving mirrors, and torchlights, providing magnified images. Convex mirrors are used as side-view or rearview mirrors in vehicles to provide a wider field of view.
What about the image formation by convex mirrors?
Convex mirrors produce virtual, erect, and usually smaller images, with the position of the image varying based on the object's location.
