What kind of image is formed by a convex mirror?

Table of Contents Show

What is Convex Mirror?
Some Important Terms
Ray Diagrams
Image formation by Convex Mirror
When The Object is Placed Between Infinity and Pole
Uses of Convex Mirrors
Reflection from Spherical Surface

Question 5 Objective Questions

Answer:

Solution :

Image formation by convex mirror

Image formed by a convex mirror is always virtual and erect.
When an object is placed at infinity, virtual image is formed at focus and the size of the image is smaller.

When an object is placed at a finite distance from the mirror, a virtual image is formed between pole and focus of the mirror and the size of the image is smaller.

Difference between convex and concave mirrors:

	Concave mirror Image	Convex mirror image
Mirrors	Inner side of the spherical mirror is reflecting.	Outer side of the spherical mirror is reflecting.
Image	Real and inverted or Virtual and erect	Virtual and erect
Size	Smaller or larger, depending on the position of the object.	Smaller than the size of the object.
Position	Depends on the position of the object.	Always within the focus.

Video transcript

"hello students welcome to Lido learning's question and answer videos my name is palibhi and i teach maths and science at ledo let's have a look at this very interesting question in front of us so we have to draw a separate diagram for a formation of virtual image of an object by a convex mirror and we also have to state the difference between conjugate convex image so let's start with the picture here so we have a smart boy over here as you can see at b and he is standing in front of a convex mirror as you can see the this is the convex mirror this is the reflecting surface right so and we can see the image of this boy at b dash so the height of the boy is a b and height of the image of the boy we can see is a dash dash so what do we see that the height is diminished image height is diminished than the object height and this is a virtual image because the rays are not actually meeting they are extended beyond the mirror and we imagine or we extend them and the rays meet virtually that is why it is called a virtual image so irrespective of where the object is kept a convex mirror always forms an erect diminished and a virtual image and this image is r it is virtual it is erect and it is diminished now let's try to understand the difference between a concave mirror and a convex mirror image so let's start with the types of mirrors so inner side of the spherical is reflecting in case of a concave mirror that is this side will be reflecting side in case of concave mirror whereas in which mirror the outer side as i already explained the outer side of the spherical mirror is reflecting what about the image the real and inverted and virtual so real inverted image will be formed most in most of the cases of concave mirror or sometimes virtual and nedec as well however in the next mirror it will always be virtual in direct image there will be no real image found in case of convex mirror what about the size of the concave mirror image smaller or larger depending upon the position of the object so there are different different cases in which different different types of image and different different positions are formed whereas in convex mirror it will be always smaller than the size of the object as you can see here irrespective of where the object is kept the convex mirror will always form a diminished image what about the position so it depends on the position of the object so image position depends on the position of the object whereas in case of convex mirror it is always within the focus so the position is always within the focus right an image position so i hope you understand point over here and you understood the differences between the mirror images found by concave as well as convex mirrors if you have any further questions please post your part below also if you like this video please don't forget to subscribe to Lido channel for more such videos thank you "

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Image formation in a convex mirror depends mainly on two possibilities. It mainly deals with the position of an object in a convex mirror whether it is at infinity or when the object is between infinity and the pole of the mirror. However, before we talk more about the formation of image in a convex mirror we shall understand a few important topics.

What is Convex Mirror?

A convex mirror is a type of spherical mirror in which the reflecting surface is the bulged out portion of the sphere, i.e. in this type of mirrors the reflecting surface bulges out towards the incident light source. Because of their shape the incident light is reflected outwards (diverged), thus they are also called diverging mirrors and thus they are not used for focusing light.

Both the laws of reflection are valid at each and every point on the mirror. The normal in this case is drawn normal to the tangent at the point of incidence, i.e. it is drawn by joining the centre of curvature of the mirror to the point of incidence. Thus, the divergence of the rays after reflection is because the normal to the surface differs at each point on the mirror.

Convex mirrors always form virtual images. This is because the focal point and the centre of curvature of the convex mirror are imaginary points and that cannot be reached. So the image is formed inside the mirror and cannot be projected on a screen. The image formed look smaller than the object from a distance but it gets larger as the object is brought closer to the mirror.

Some Important Terms

1. Pole: It is the centre of the reflecting surface of a spherical mirror. It lies on the surface of the mirror and it is usually denoted by P.

2. Centre of curvature: The centre of the sphere formed by the reflecting part of a spherical mirror is called the centre of curvature. It is generally denoted by C. this is not a part of the mirror and it lies outside the reflecting surface of the mirror. For a convex mirror, it lies behind the mirror.

Also Read: Mirror Formula For Spherical Mirrors

3. Radius of curvature: It is the radius of the sphere formed by the reflecting part of the sphere. It is represented by R.

4. Principal axis: It is the straight-line parring through the pole and centre of curvature of the spherical mirror. This is normal to the mirror at its pole.

5. Principal focus: The incident rays coming parallel to the principal axis after reflection appear to diverge from a common point on the principal axis, this point is called the principal focus of a convex mirror. It is usually denoted by F.

6. Focal length: It is the distance between the pole and the principal focus of the mirror. It is denoted by f.

Ray Diagrams

Ray diagrams are necessary for understanding the formation of an image by a convex mirror. For constructing ray diagrams and to learn the image formation, we should consider at least two incident rays coming from the object.

The intersection of these two reflected rays gives the position of an image of the object. In case of a convex mirror any of the following four ray diagrams can be used for locating the image formed:

a) When the ray is parallel to the principal axis. After reflection, the rays appear to diverge from the principal focus of a convex mirror.

b) When a ray is directed towards the principal focus of a convex mirror, after reflecting it will emerge parallel to the principal axis.

c) When a ray is directed in the direction of the centre of curvature of a convex mirror the rays will be reflected along the same path. This occurs because the incident rays fall on the mirror along the normal to the reflecting surface.

d) When a ray incident is oblique to the principal axis and towards the pole of the mirror on the convex mirror, it is reflected obliquely. The incident and reflected rays follow the laws of reflection at point P, making equal angles with the principal axis.

Image formation by Convex Mirror

Rays emerging from a point actually meet at another point after reflection, and that point is called the image of the first point. The image is real if the rays converge to the point and it is virtual if the rays do not meet it but appear to diverge from a point when the rays are produced backwards.

During image formation we assume that the rays are paraxial, i.e., they are incident at points close to the pole P of the mirror and make small angles with the principal axis. For a convex mirror, we consider two positions of the object before the mirror.

When an object is placed at infinity.
When the object is placed between infinity and the pole of the mirror.

For the image formation by a convex mirror in this condition, we consider two rays parallel to the principal axis and one directed towards the pole of the mirror originating from the object. These rays after reflection form an image at F, the principal focus of the mirror, which is behind the convex mirror. The image thus formed is highly diminished, virtual and erect.

When The Object is Placed Between Infinity and Pole

In this situation of the image formation by a convex mirror, we consider two different rays emerging from the object. One parallel to the principal axis and the other directed towards the centre of curvature of the mirror. These rays after reflection form an image between the pole (P) and the focus (F) behind the mirror. The image thus formed is diminished, virtual and erect.

Position of the object	Position of the image	Size of the image	Nature of the image
At infinity	At focus, F, behind the mirror	Highly diminished and pointed in size	Virtual and erect
Between infinity and pole of the mirror	Between P and F, behind the mirror	Diminished	Virtual and erect

Uses of Convex Mirrors

Because they have wider fields of view, as they are curved outwards they are commonly used in automobile side mirrors.
Convex mirrors are also a good security device because single security personnel could see large portions of the store while monitoring from a single location.
They are used in driveways and roads, to provide safety to all the bikers and drivers at curves and other places where there is a lack of visibility.
They are also used in ATMs as a handy security feature that allows the user to see what is happening behind them.

Reflection from Spherical Surface

The convex mirror will not form a real image, it can only form a virtual image.

The convex mirrors always make the images look smaller and wider than the actual object, but the image formed gets bigger and bigger as the object gets closer to the mirror.

Convex mirrors are used in cars, hallways of buildings etc.

Yes. The image formed by the convex mirror is laterally inverted.