10th Class Physics Chapter 9: Light Reflection and Refraction

The fundamental laws of reflection are: (i) The angle of incidence is equal to the angle of reflection, and (ii) The incident ray, the normal to the mirror at the point of incidence, and the reflected ray all lie in the same plane. These laws apply to both plane and curved mirrors.

Images formed by plane mirrors are always virtual, erect, equal in size to the object, and laterally inverted. On the other hand, images formed by curved mirrors can vary in size, orientation, and nature depending on whether the mirror is concave or convex.

Concave mirrors curve inward and converge light rays to a focal point, forming real or virtual images based on the object's position. Convex mirrors curve outward and diverge light rays, always forming virtual, smaller, and upright images.

<p>The centre of curvature for concave mirrors lies in front of the mirror, while for convex mirrors, it lies behind the mirror. This difference impacts the reflective properties as it affects how light is reflected and the type of images that are formed by the mirrors.</p> Signup and view all the answers

<p>The principal axis of a mirror is a line passing through the pole and the center of curvature. It is normal to the mirror at its pole. Understanding the principal axis helps in visualizing how light rays interact with the mirror and where images are formed.</p> Signup and view all the answers

<p>The principal focus of a concave mirror is the point on its principal axis where parallel rays of light converge after reflection.</p> Signup and view all the answers

<p>The focal length would be half of the radius of curvature. Therefore, the focal length of the mirror would be 10 cm.</p> Signup and view all the answers

<p>Convex mirror</p> Signup and view all the answers

<p>Convex mirrors are preferred as rear-view mirrors in vehicles because they provide a wider field of view, always produce an erect image, and enable the driver to see a larger area behind the vehicle.</p> Signup and view all the answers

<p>The New Cartesian Sign Convention states that distances are measured from the pole of the mirror with specific signs (+ or -) depending on the direction. Objects are always placed to the left of the mirror, and convention is used to determine the nature of the image produced.</p> Signup and view all the answers

<p>The mirror formula is derived from geometric principles using ray diagrams. It is significant as it mathematically relates the object distance, image distance, and focal length in spherical mirrors, allowing for accurate image formation predictions.</p> Signup and view all the answers

<p>Magnification in spherical mirrors is the ratio of the height of the image to the height of the object. It is calculated by dividing the height of the image by the height of the object. The sign of the magnification indicates whether the image is real or virtual.</p> Signup and view all the answers

<p>The refractive index of a medium is calculated by dividing the speed of light in air by the speed of light in the medium.</p> Signup and view all the answers

<p>The refractive index helps in understanding how light propagates and bends in different materials based on their speed of light.</p> Signup and view all the answers

<p>1.33</p> Signup and view all the answers

<p>2.42</p> Signup and view all the answers

<p>The principal focus is the point where light rays parallel to the principal axis converge (in a concave mirror) or appear to diverge from (in a convex mirror), directly related to the focal length of the mirror.</p> Signup and view all the answers

<p>For spherical mirrors, when the radius of curvature (R) equals 2 times the focal length (R = 2f), the principal focus is positioned midway between the pole and the center of curvature. This relationship affects how images are formed by concave mirrors.</p> Signup and view all the answers

<p>Images formed by concave mirrors can be real or virtual, enlarged or diminished, depending on the position of the object. The nature, position, and size of the image change relative to the positions of the object, principal focus, and center of curvature.</p> Signup and view all the answers

<p>The nature, position, and size of the image formed by a concave mirror vary based on the object's position relative to the principal focus (F), center of curvature (C), and pole (P). The image can be real or virtual, enlarged or diminished, depending on these positions.</p> Signup and view all the answers

<p>Ray diagrams are constructed by considering rays that are parallel to the principal axis, pass through the principal focus, or reflect back along the same path after hitting the mirror. These rays help locate the image of an extended object formed by spherical mirrors. Examples from concave and convex mirrors illustrate how different rays interact and form images.</p> Signup and view all the answers

<p>Rays directed towards the principal focus, after reflection in concave mirrors, pass through the same focus, while in convex mirrors, they appear to diverge from the focus. These rays are vital in constructing ray diagrams as they help determine the path of light after reflection.</p> Signup and view all the answers

<p>The concentration of the sunlight at a point generated heat, causing the paper to burn.</p> Signup and view all the answers

<p>The point on the principal axis where parallel rays of light converge or appear to diverge after refraction.</p> Signup and view all the answers

<p>It becomes smaller</p> Signup and view all the answers

<p>A concave lens will always produce a virtual, erect, and diminished image.</p> Signup and view all the answers

<p>True</p> Signup and view all the answers

<p>3.00 m</p> Signup and view all the answers

<p>1.50 m</p> Signup and view all the answers

<p>1.15 m behind the mirror</p> Signup and view all the answers

<p>0.23</p> Signup and view all the answers

<p>4.0 cm</p> Signup and view all the answers

<p>37.5 cm</p> Signup and view all the answers

<p>6.0 cm</p> Signup and view all the answers

<p>16 cm</p> Signup and view all the answers

<p>37.5 cm behind the mirror</p> Signup and view all the answers

<p>Clay</p> Signup and view all the answers

<p>At twice the focal length</p> Signup and view all the answers

<p>A convex lens of focal length 5 cm</p> Signup and view all the answers

<p>dioptre</p> Signup and view all the answers

<p>The focal length of the lens is $\frac{1}{1.5} = 0.67$ meters (67 cm). The prescribed lens is converging.</p> Signup and view all the answers

<p>The lens formula relates to object-distance (u), image-distance (v), and focal length (f).</p> Signup and view all the answers

<p>Magnification for a lens is the ratio of image height to object height. It is related to v and u through the formula m = v/u.</p> Signup and view all the answers

<p>The power of a lens is defined as the reciprocal of its focal length. The sign of the power indicates the type of lens - positive for convex and negative for concave.</p> Signup and view all the answers

<p>The SI unit of power of a lens is 'dioptre' denoted by 'D'. 1 dioptre is the power of a lens with a focal length of 1 meter.</p> Signup and view all the answers

<p>Multiple lenses can be combined by summing their individual powers to increase magnification and sharpness of an image.</p> Signup and view all the answers

<p>The relationship is described by the lens formula: 1/v + 1/u = 1/f.</p> Signup and view all the answers

<p>The New Cartesian Sign Conventions dictate that distances are positive in the direction of incident light and negative in the opposite direction.</p> Signup and view all the answers

<p>Magnification formula is m = v/u, where m is the magnification, v is image distance, and u is object distance.</p> Signup and view all the answers