Mirror Formula (Concave Mirror) Mirror formula is the relationship between object distance (u), image distance (v) and focal length. A virtual image occurs when light rays do not actually meet at the image. The image A 1 B 1 is formed at a distance v from the mirror. Before that can be done, the focal point must first be defined. A “virtual” image occurs when light rays do not actually meet at the image. A completed ray diagram is shown in. In a concave mirror, the principal axis is a line that is perpendicular to the center of the mirror. A summary of the properties of convex mirrors is shown below: CC licensed content, Specific attribution, http://en.wikipedia.org/wiki/Optics%23Reflections, http://www.boundless.com//physics/definition/virtual-image, http://www.boundless.com//biology/definition/concave. It shows the image A′B′ (in this case, real) of an object AB formed by a concave mirror. An image formed by reflection may be real or virtual. If the light ray hit the object at a 30 degree angle, it will be reflected back at a 30 degree angle. The distance to the focal point from the mirror is called the focal length. The use of these diagrams was demonstrated earlier in Lesson 3 and in Lesson 4.Ray diagrams provide useful information about object-image relationships, yet fail to provide the information in a quantitative form. A summary of the properties of the concave mirrors are shown below: converging real image inverted image in front of mirror. From the figure given above, it is obvious that the object AB is placed at a distance of U from P which is the pole of the mirror. The use of these diagrams was demonstrated earlier in Lesson 3 and in Lesson 4.Ray diagrams provide useful information about object-image relationships, yet fail to provide the information in a quantitative form. A real image occurs when light rays actually intersect at the image, and is inverted, or upside down. Draw the image of the object, by using the principle that the image is placed at the same distance behind the mirror that the object is in front of the mirror. The center of curvature is the point at the center of the sphere and describes how big the sphere is. The object is the source of the incident rays, and the image is formed by the reflected rays. The mirror equation $$\frac{1}{v}+\frac{1}{u}=\frac{1}{f}$$ holds good for concave mirrors as well as convex mirrors. The image A 1 B 1 is formed at a distance 'v' from the mirror. The way that we can predict how a reflection will look is by drawing a ray diagram. Mirror Formula Derivation. The steps taken to draw are the same as those in a plane mirror. Thus, point A′ is image point of A if every ray originating at point A and falling on the concave mirror after reflection passes December 30, 2012. Draw the plane mirror as a straight line on a principal axis. The reflected rays diverge. In addition, the image in the first mirror may act as an object for the second mirror, so the second mirror may form an image of the image. Before that can be done, the focal point must first be defined. The image size is also the same as the object size. shows these first three steps. We can see from the figure that this focal length is also equal to half of the radius of the curvature. These are the steps you follow to draw a ray diagram: The angle in which a light ray hits the mirror is the same angle in which it will be reflected back. Instead, you “see” the image because your eye projects light rays backward. Filed Under: Class 10, Light-Reflection and Refraction Tagged With: image distance, magnification, mirror formula, object distance, real image, virtual image About Mrs Shilpi Nagpal Author of this website, Mrs Shilpi Nagpal is MSc (Hons, Chemistry) and BSc (Hons, Chemistry) from Delhi University, B.Ed (I. P. University) and has many years of experience in teaching. The figure shows an object AB at a distance u from the pole of a concave mirror. The easiest way to visualize what a image will look like in this type of mirror is a ray diagram. The position of the image is obtained by drawing a ray diagram. A mirror is a reflective surface that does not allow the passage of light and instead bounces it off, thus producing an image.