Ask your friend to wear the cap and see his image in the mirrors. Pro Lite, Vedantu The number of images formed by two adjacent plane mirrors depends on the angle between the mirror. Explain reflection of light from a plane mirror. Adjust the angle between the mirrors so that you see two images of yourselves (with cap and strips clearly visible). Light always has regular reflection on plane mirrors. Reduce the angle between mirrors and observe multiple images of the candle which makes a beautiful scene. Though an average person is not familiar with this technical term, they can easily relate that to the normal mirrors which are polished on one side with mercury so that they can reflect light falling on them. Place a lighted candle in the space between the two mirrors. They can easily reflect light in various directions, undergoing certain phenomenon namely reflection, refraction or absorption. \end{align} We verify this formula in this experiment. Place both the mirrors vertically with 180 degree angle between the them. As the angle between the mirrors gradually decreased, not only the candle but the mirrors themselves get imaged in one another. To see any image in the mirror a person should be in the line of sight of the mirror, as when the person is in the line of sight of the mirror then the reflected ray reaches that person’s eye through which anyone can see the image of the object if they are in the line of sight of the mirror, this is because light has the property of moving in a straight line. Place both the mirrors side by side and fix the junction where they meet with a cello tape. For e.g. Locating an Image in a Plane Mirror. In this type of reflection, the incident ray reflected along the reflected ray does not have the same angle as that of the incident ray. While the angle of reflection can be defined as the angle formed at the point of contact of the reflected ray and the surface normal of the plane mirror. The real images of the objects are generally formed by the curved mirrors as in the curved mirrors the rays of light get reflected and pass through the mirror to form the real image. When the angle between the two mirrors is 180 degree they together act like a single mirror so that only one image is visible. Some examples of a real image are the image formed on the retina of the eye or the image formed on the film of the camera. The real images formed by the curved mirrors are always inverted. To find out how many images are formed when plane mirrors are tilted at an angle, use the formula N=360/a-1 , wherein N is the number of images formed and a is the given angle. If $$\theta$$ (in degrees) is angle between the plane mirrors then number of images are given by, \begin{align} n=\frac{360}{\theta}-1. So due to this, the observer sees the image at the same distance as the object is from the mirror. Let, the angle is x If the value of 360/x is even, then we will use the formula no. Also on measuring the distance of object u and the distance of image v, it is found that the image is formed at the same distance behind the plane mirror as the object is in front of the mirror. the mountains covered with lakes, the image of the mountains shown in the lake is perfect as the lake is the smooth surface. Take two plane mirrors (without frame). One of the main characteristics of the plane mirror is that the image formed by the plan mirror is inverted, that means if you raise your left hand then the image of the plan mirror will show the right hand going upwards. For e.g. We verify this formula in this experiment. You will now observe more and more numbers of images of the candle. This means that the distance PB from the object to the mirror is the same as the distance BQ from the mirror to the image. There are generally two laws of reflection which can be stated as follows: 1. Now the reflected rays PA and OC are diverging rays and therefore cannot meet each other actually in front of the mirror. We have to see the rays coming from the object to see it. In this way one observes a lot many images. These angles are $$\theta_\text{measured}$$. Characteristics of an Image Formed by a Plane Mirror. The number of images formed by two adjacent plane mirrors depends on the angle between the mirror. Images formed by the plane mirrors are always virtual in nature. when the light hits a bird which is a rough surface, the reflected light scatters in all direction, when reaches our eye and hits the retina it gets processed in the brain from an electrical signal to form an image of a bird. Suppose, an object is placed at 5 cm in front of a plane mirror then its image will be at 5 cm behind the plane mirror. An image formed by the plan mirror is of the same magnification as that of the object. You will see single image of the candle in mirror. The image produced is on the opposite side of the mirror with the distance of the image from the surface is equal to the distance of the object from the surface, that is the reason why a person can see what’s exactly behind him. The image formed by a plane mirror is at the same distance behind the mirror as the object is in front of it. Given picture below shows how we can find the image of a point in plane mirrors. To get complete image of object AB join the points A’ and B’ by a dotted line. Why this happened? of images= 360/x -1 If the value of 360/x is odd, then we use the formula no. Some examples of Virtual image are the image formed by a magnifying glass when used to look at the small objects. An incident ray of light AP from the point A of the object AB falls normally on the mirror at point P, and is thus reflected back in the same path, along PA. If the angle between the mirrors is finally decreased to zero, infinite images are expected to be formed. (iv) The image formed by a mirror is laterally inverted. This setup is also used to make a funny game. To see any image in the mirror a person should be in the line of sight of the mirror, as when the person is in the line of sight of the mirror then the reflected ray reaches that person’s eye through which anyone can see the image of the object if they are in the line of sight of the mirror, this is because light has the property of moving in a straight line. An incident ray of light AP from the point A of the object AB falls normally on the mirror at point P, and is thus reflected back in the same path, along PA. The reflected ray, the normal at the point of incidence and the incident ray lie on the same plane. Now, by gradually decreasing the angle between the mirrors observe the images being formed. Order him to touch the white or black strip quickly. Now place an extended object AB of size h on the left side of the mirror at a distance u. Place a lighted candle in the space between the two mirrors. In the plane mirrors, we require at least two rays through which the image of the object can be formed by observing the endpoints of the 2 light rays taken. Draw the ray diagram when angle between two mirrors is 90 degree. To find out the position of the image formed by a plane mirror after reflection, take a plane mirror MM’. On extending backward these rays appear to meet at point A’ at a distance v. So A’ is the virtual image of point A of the object AB. 4. You will observe many images of the candle which makes a beautiful scene. Plane mirrors can be found very easily in our daily life. The plane mirror can be polished with various materials that can be used for various purposes but all the mirrors function the same way regardless of their constructing material. Similarly, if the angle between the mirrors is increased the number of images decreases and when this angle is 180 degree, only one image is visible. The second ray of light AO strikes the mirror at point O and gets reflected along the path OC. That is why when the angle between the mirrors is decreased one observe image within image, and image within that image, and so on. A plane mirror can be easily defined as the mirrors those are flat in surface and are without any inward or outward curve. Sorry!, This page is not available for now to bookmark. Pro Lite, CBSE Previous Year Question Paper for Class 10, CBSE Previous Year Question Paper for Class 12. Place both the mirrors at a small angle apart in the upright position on the floor. Test Your Understanding and Answer These Questions: Rules for Obtaining Images by Spherical Mirrors. A plane mirror makes an image of objects in front of the mirror; these images appear to be behind the plane in which the mirror lies. Now you will be able to open and close the mirrors like a book. Calculate $$\theta_\text{calculated}$$ for $$n=1,3,5,7,9$$ by using the formula given above. Vedantu academic counsellor will be calling you shortly for your Online Counselling session. Images formed by the plane mirrors are erect/ upright and is of the same size as of the object. (i) The size of the image is the same as the size of the object. Pro Lite, Vedantu There are two types of reflection in plane mirrors, which are: The Specular / Regular reflection, as the name says, provides the perfect image of the object without any distortion. The important phenomenon of the plane mirror is that the reflections of the objects form the virtual image with the same magnification, size, and distance of the same as the object really are. In the same manner the virtual image B’ will be formed behind the mirror from the incident rays BO and BE falling on the mirror from point B of the object. Now, measure the maximum angle between two mirrors when you get 1, 3, 5, 7, and 9 images. (iii) A virtual and erect image is formed. The image formed by the plane mirror has the same magnification, size, and distance of the object. If $$\theta$$ (in degrees) is angle between the plane mirrors then number of images are given by. The angle of incidence (i) is always equal to the angle of reflection (r). The image formed by the plane mirror is of the same size as the object. 2. The virtual image of the objects is generally formed by the plane mirrors as the plane mirrors are polished on one side so the reflection of the object strikes the mirror and get reflected towards the direction of the observer's eye. Following are the characteristics of an image formed by a plane mirror: It is formed at the same distance behind the mirror as the object is in front of the mirror. (ii) The distance of the object in front of the mirror is equal to the distance of the image behind the mirror. Here is the list of characteristics of an image formed by a plane mirror. Think how this happens? In the case of a plane mirror, the angle at which the ray is reflected is equal to the angle at which the ray of light is incident, regardless of whether the image is real or virtual, where the angle of incidence is the angle formed at an imaginary surface which is normal to the mirror (which is perpendicular to the surface) at the point of incidence. 3. 2. On joining the points A’ and B’ we find that the image formed by a plane mirror is virtual, erect and of the same size as that of object. The image of the object depends on the geometrical line through which a person sees in the mirror, though all the line of sight will provide the image of the object, as long as the person‘s eye is in line with the mirror. 1. A straight line drawn from part of an object to the corresponding part of its image makes a right angle with, and is bisected by, the surface of the plane mirror.

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