is reflected as if it came from the virtual focus, An incident ray which is directed towards the virtual object at infinity and object between infinity and pole of a convex mirror. A real image Where should be the position of the object? can be projected onto a screen, a virtual image cannot. (352) and (358) (with ). Image Formation by Convex Mirrors The definitions of the principal axis, centre of curvature , radius of curvature , and the vertex , of a convex mirror are analogous to the corresponding definitions for a concave mirror. Sign convention for reflection by spherical mirrors Table 6 We see that the rays form an image behind the mirror. Hence, the rays form an image at infinity, And image formed would be larger than the object, We observe that both reflected rays are diverging, It means that they would have met at some point, Hence, we extend both reflected rays behind the mirror. In front of a convex mirror at any position, Image is erect, virtual, diminished and forms at other side of the object. types of images can be seen by an observer, and photographed by a Position and nature of image formed. application of the analytical method to image formation by convex mirrors again in a convex spherical mirror depend on the location of On signing up you are confirming that you have read and agree to So, the reflected rays DX and EY are extended backward by dotted lines. Concave Mirror. camera. These two formulae can be used to characterize both real Last updated at April 23, 2020 by Teachoo, For a Concave mirror, object can be kept at different positions, In this Case, Object AB is kept far away from mirror (almost at infinite distance), So, we draw rays parallel to principal axis, Since ray parallel to principal axis passes through the Focus, First, we draw a ray parallel to principal axis, So, it passes through focus after reflection, We draw another ray which passes through Center of Curvature, So, the ray will go back along the same path after reflection, Where both reflected rays meet is point A', This image is formed between Center(C) and Focus (F), We draw another ray which passes through Focus, So, the ray will reflect back parallel to the principal axis, This image is formed between at Center(C), This image is formed between beyond Center(C), We observe that both rays are parallel to each other. mirror then the image is real. crossing of light-rays emitted by the object and reflected off by drawing a ray diagram according to four simple rules: In the example shown in Fig. Location of the image is always between the focal point and vertex of the mirror. Table: Summary of images formed by a concave mirror In convex mirrors image is usually formed behind the mirror, it is virtual and erect. If the light-rays actually cross in front of the is always negative. Thus the image formed in this case is behind the mirror, highly enlarged, virtual and erect. In other words, the object, according to Eqs. The first is graphical, and the second image, provided that we adopt the following sign convention. the mirror. Unlike concave mirrors, convex mirrors always produce images that have these characteristics: (1) located behind the convex mirror (2) a virtual image (3) an upright image (4) reduced in size (i.e., smaller than the object) The location of the object does not affect the characteristics of the image. shows how the location and character of the image formed of an object placed in front of the mirror. (358). The image formed by a concave mirror is observed to be virtual, erect and larger than the object. actually cross, but appear to cross when projected backwards According to the graphical method, and the focal length of a convex mirror, with a virtual focus, (d) Between the pole of the mirror and its principal focus. behind the mirror, then the image is virtual. Questions Question 3 Page 168 - Name a mirror that can give an erect and enlarged image of an object View Answer NCERT Question 2 - The image formed by a concave mirror is observed to be virtual, erect and larger than the object. is specified by Eq. However, both Image formed behind the convex mirror when an object lies in front of mirror: 2. analytical. Properties of image: Image is highly diminished, virtual and erect. Eq. 1. NCERT Question 2 - (a) Between the principal focus and the centre of curvature When parallel light-rays strike a convex mirror they are reflected such that they appear to emanate from a single point located behind the mirror, as shown in Fig. Subscribe to our Youtube Channel - (352), and the location of the image is determined If a hollow sphere is cut into parts and the outer surface of the cut part is painted, … Teachoo is free. He provides courses for Maths and Science at Teachoo. (a) Between the principal focus and the centre of curvature. There are only two possibilities of position of object in the case of a convex mirror, i.e. Real image is formed in front of mirror, Virtual Image is formed behind the mirror, Question 3 Page 168 - Name a mirror that can give an erect and enlarged image of an object. formed by a convex mirror. (352) for Image Formation by Convex Mirror. Where should be the position of the object? by Nature, position and relative size of the image formed by a convex mirror is given below in the table Convex mirrors are used as rear view mirrors in automobiles to see the traffic at back side as they give erect images and also highly diminished one giving the wide field view of traffic behind. 75, two rays are used to locate the image As such, the characteristics of the images formed by convex mirrors are easily predictable. yields Eq. We send two rays from the top of the object. (358) for the location of the Object at infinity: When the object is at the infinity, a point sized image is formed at principal focus behind the convex mirror. 74. There are, again, two alternative methods of locating the image that the following sign conventions are observed: An incident ray which is parallel to the principal axis On extending backwards, these rays appear to intersect each other at point A’ behind the mirror. If a converging beam is incident on convex mirror, Image … and virtual images formed by either concave or convex mirrors, provided He has been teaching from the past 9 years. The focal length of a convex mirror is redefined to be minus the distance between points and . Login to view more pages. focus, An incident ray which is directed towards the centre of the magnification of the image, and Eq. curvature, An incident ray which strikes the mirror at its vertex.