{"id":3315,"date":"2023-10-04T14:09:12","date_gmt":"2023-10-04T14:09:12","guid":{"rendered":"http:\/\/localhost\/ecole9ja\/?p=3315"},"modified":"2023-10-04T14:10:36","modified_gmt":"2023-10-04T14:10:36","slug":"week-10-ss2-second-term-physics-notes","status":"publish","type":"post","link":"https:\/\/ecolebooks.com\/nigeria\/posts\/week-10-ss2-second-term-physics-notes\/","title":{"rendered":"Week 10 &#8211; SS2 Second Term Physics Notes"},"content":{"rendered":"<p><strong>WEEK TEN<br \/>\n<\/strong><strong>LIGHT WAVES<br \/>\n<\/strong><\/p>\n<ul>\n<li>Light waves\n<\/li>\n<li>Source of Light waves\n<\/li>\n<li>Reflection of Light waves\n<\/li>\n<li>Reflection of plane and curved mirrors\n<\/li>\n<\/ul>\n<p>\u00a0<strong>Light waves<br \/>\n<\/strong>Light wave is a visible source of energy. It is also a wave motion. It has a very short wavelength of 5\u00d710<sup>-4<\/sup>mm. Light travels at a speed of 3.0\u00d710<sup>8<\/sup>ms<sup>-1<\/sup><br \/>\n\t\t<strong>Source of Light waves<br \/>\n<\/strong>There are various sources of light: natural and artificial, luminous and non-luminous. Natural sources of light include the sun and the stars. Artificial sources of light are the candle, electric torch, the electric lamp, incandescent, arc light and fluorescent light.<strong><br \/>\n\t\t\t<\/strong><em>Self-luminous or luminous sources of light<\/em>  are those that generate and emit light by themselves e. g. the sun, stars, fire flies and some deep sea fishes  <strong><br \/>\n\t\t\t<\/strong><br \/>\n\t\t<em>Non-luminous objects<\/em> are seen when they reflect or throw back light from a luminous objects. Examples of non-luminous objects are moon, paper, mirror, wall etc.<br \/>\nWhen light falls on such surface, it is may be absorbed, transmitted or reflected, sometimes a combination of the above processes may occur<br \/>\n<strong>Light rays and beams<br \/>\n<\/strong>A ray is the direction of the path in which light is travelling. It is represented by a straight-line with an arrowhead<br \/>\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0A light ray<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100423_1409_Week10SS2S1.png\" alt=\"\"\/><br \/>\n\t\tA beam is a collection of two or more rays of light. Beams can be parallel, convergent or divergent.<br \/>\nA parallel beam is two or more rays travelling in the same direction but can never intersect each other.<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100423_1409_Week10SS2S2.png\" alt=\"\"\/><br \/>\n\t\t<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100423_1409_Week10SS2S3.png\" alt=\"\"\/><img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100423_1409_Week10SS2S4.png\" alt=\"\"\/><img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100423_1409_Week10SS2S5.png\" alt=\"\"\/>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0A parallel beam<br \/>\nA beam of light is said to be convergent when they meet at a point<\/p>\n<p>\u00a0<br \/>\n\u00a0<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100423_1409_Week10SS2S6.png\" alt=\"\"\/><\/p>\n<p>\u00a0<br \/>\n\u00a0<br \/>\n\u00a0<br \/>\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0A convergent beam<\/p>\n<p>\u00a0The divergent beam occurs when a collection of light rays has the same source is spread out apart. <\/p>\n<p>\u00a0<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100423_1409_Week10SS2S7.png\" alt=\"\"\/><\/p>\n<p>\u00a0<br \/>\n\u00a0<br \/>\n\u00a0<br \/>\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0A divergent beam<\/p>\n<p>\u00a0<strong>RECTILINEAR PROPAGATION OF LIGHT<\/strong><br \/>\n\t\tThe phenomenon of light travelling in straight line is known as rectilinear propagation of light. It can be demonstrated by placing a candle flame at the end of a straight pipe, light of the flame will be seen clearly at the other side of the pipe. If the pipe is then bent and the process repeated, nothing will be seen at the other end, this clearly shows that light travels in straight line. Two natural effects that result from the rectilinear propagation of light are the formation of eclipse and shadow, The principle of operation of the pin hole camera also depends on the fact that light travels in straight lines.<\/p>\n<p>\u00a0<strong>SHADOW<\/strong><br \/>\n\t\tA shadow is an area in which light rays from a source cannot reach. It is produced by the obstruction of light by an opaque object. There are two types of shadow: partial (penumbra) shadow and total (umbra) shadow. If the light source is large, the shadow formed consist of two parts, a completely dark area known as umbra and an outer grey area known as penumbra or partial shadow. In the umbra region, the light from the source is completely blocked by the opaque body. In the penumbra region, the light is partially blocked by the opaque object. The inner region of the shadow receives less than the outer parts. Thus the penumbra becomes brighter from the umbra and outwards.<br \/>\n<strong>ECLIPSE<\/strong><br \/>\n\t\tAn eclipse is a result of a shadow cast by one heavenly body on another. The sun being a luminous body and it is in the middle while the earth and the moon revolves round the sun. If the moon is between the sun and the earth, the shadow of the moon will be cast on the earth&#8217;s surface.<br \/>\nThere are two types of the eclipse. Viz:<\/p>\n<ol>\n<li>\n<div>Eclipse of the sun (solar eclipse): here the moon comes between the sun and the earth in a straight line\n<\/div>\n<\/li>\n<li>\n<div>Eclipse of the moon (lunar) eclipse: in this case, the earth comes in between the sun and the moon.\n<\/div>\n<\/li>\n<\/ol>\n<p><strong>PIN HOLE CAMERA<\/strong><br \/>\n\t\tIt consists of a light proof box, one end of which has a small hole made with a pin or needle point. The opposite end has a screen made with tracing paper or ground glass. Light from an object in front of the pinhole passes through it and form an image on the screen. If the screen is replaced with a photographic paper or film, a picture of the object can be taken with the pinhole camera.<br \/>\nWhen using the pinhole camera to take pictures of an object, long exposure is necessary to allow sufficient light to enter the box through the pin hole. The image formed on the screen of the pinhole camera will be seen more clearly if external light is excluded by covering head and camera with a dark cloth.<br \/>\nThe image formed on the screen of the pinhole camera is inverted<br \/>\n<strong>Linear magnification<br \/>\n<\/strong>Magnification is defined as the ratio of the size (or height) of the image to the size (or height) of the object<br \/>\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0&#8212;1<br \/>\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0&#8212;2<\/p>\n<p>\u00a0<strong>Reflection of Light waves<br \/>\n<\/strong>Reflection is the bouncing back of light waves when it strikes a surface.<br \/>\n<strong>Reflection of plane mirrors<br \/>\n<\/strong>There are two types of reflection:<br \/>\n1.\u00a0\u00a0\u00a0\u00a0Regular Reflection<br \/>\n2.\u00a0\u00a0\u00a0\u00a0Diffuse Reflection or Irregular Reflection<br \/>\nIn regular reflection, parallel rays of light incident on a smooth or polished surface are reflected as parallel rays in one direction. <\/p>\n<p>\u00a0<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100423_1409_Week10SS2S8.png\" alt=\"\"\/><br \/>\n\t\tIncident\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Reflected<br \/>\nRays \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Rays<\/p>\n<p>\u00a0<br \/>\n\u00a0<br \/>\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Regular reflection<\/p>\n<p>\u00a0<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100423_1409_Week10SS2S9.png\" alt=\"\"\/>In diffused or irregular reflection, parallel rays of light incident on a rough or irregular surface are reflected in various directions<\/p>\n<p>\u00a0<br \/>\n\u00a0<br \/>\n\u00a0<br \/>\n\u00a0Incident <\/p>\n<p>\u00a0<br \/>\n\u00a0<br \/>\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Diffuse or scattered reflection<\/p>\n<p>\u00a0<strong>LAWS OF REFLECTION<\/strong><br \/>\n\t\tThe first law of reflection states that the incident ray, the reflected ray and the normal at the point of incidence all lie on the same plane<br \/>\nThe second law of reflection states that the angle of incidence (i) is equal to angle of reflection (r).<\/p>\n<p>\u00a0<strong>IMAGE FORMATION BY A PLANE MIRROR<br \/>\n<\/strong><strong>CHARACTERISTICS OF IMAGE FORMED BY PLANE MIRROR<br \/>\n<\/strong>1.\u00a0\u00a0\u00a0\u00a0It is the same size as the object<br \/>\n2.\u00a0\u00a0\u00a0\u00a0It is virtual<br \/>\n3.\u00a0\u00a0\u00a0\u00a0It is laterally inverted<br \/>\n4.\u00a0\u00a0\u00a0\u00a0It is upright<br \/>\n5.\u00a0\u00a0\u00a0\u00a0It is far behind the mirror as the object is in front of the mirror<br \/>\n<strong>IMAGE<br \/>\n<\/strong>There are two types of image:<br \/>\n1.\u00a0\u00a0\u00a0\u00a0Real image<br \/>\n2.\u00a0\u00a0\u00a0\u00a0Virtual image<br \/>\nA real image is one that can be caught on a screen.  Light rays actually pass through real image.  A virtual image is one that cannot be caught on a screen.  It is one through which rays do not actually pass but which is nevertheless visible to the eye.<br \/>\n<strong>LATERAL INVERSION<br \/>\n<\/strong>The effect on plane mirror on objects placed in front of it whereby the appearance of the image looks like a reversal of the object is known as lateral inversion<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100423_1409_Week10SS2S10.png\" alt=\"\"\/><\/p>\n<p>\u00a0<br \/>\n\u00a0AM\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0MA<\/p>\n<p>\u00a0<strong>IMAGES FORMED BY INCLINED MIRROR<br \/>\n<\/strong>When two mirrors are placed at an angle to each other, the number of images formed is given by:<br \/>\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0&#8212;3<br \/>\n\u00a0\u00a0\u00a0\u00a0N = Number of images<br \/>\n\u04e8 = Angle of inclination<br \/>\nWhen \u04e8 = 180<sup>0<\/sup>, the two mirrors will act as a single mirror and therefore formed only one image. When \u04e8 = O, the two mirrors are parallel to each other and the image of object placed between them will be at infinity.<br \/>\n<strong>EFFECT OF MIRROR ROTATION ON REFLECTED RAY-MIRRO GALVANOMETER<br \/>\n<\/strong>If the direction of an incident ray on a mirror is kept constant and the mirror is rotated through twice that angle.  This fact is utilized in mirror galvanometer (to measure very small electric current) and in the navigator&#8217;s sextant.<\/p>\n<p>\u00a0<strong>Example<br \/>\n<\/strong>The reflection of a narrow beam of light incident normally on a plane mirror falls on a metre rule parallel to the mirror and at a distance of 1m.  Calculate the angle of rotation of the mirror if the reflected beam is displaced 21.26cm along the metre-rule when the mirror rotated.<\/p>\n<p>\u00a0Angle ONP = 2 \u04e8<br \/>\nTan 2 \u04e8 = 21.26<br \/>\n\t\t\u00a0\u00a0\u00a0\u00a0     100<br \/>\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0= 0.2126<br \/>\n\u00a0\u00a0\u00a0\u00a02 \u04e8 = tan<sup>-1<\/sup> (0.2126)<br \/>\n\u00a0\u00a0\u00a0\u00a02 \u04e8 = 12<sup>0<\/sup><br \/>\n\t\t\u00a0\u00a0\u00a0\u00a0   \u04e8 = 6<sup>0<\/sup><\/p>\n<p>\u00a0<strong>USES OF PLANE MIRROR<br \/>\n<\/strong>It is used in periscope<br \/>\nIt is used in kaleidoscope<br \/>\nIt is used in sextant<br \/>\n<strong>Reflection of curved mirrors<br \/>\n<\/strong>Curved mirrors differ in size, shape and direction of their curvature. In respect of shape, we have spherical and parabolic mirrors.<br \/>\nThere are two types of spherical mirrors \u2013 concave and convex mirrors<\/p>\n<ol>\n<li>\n<div>Concave mirrors \u2013 the concave mirrors are hollowed-out toward the incident light like the inside surface of a spoon. It is also called a converging mirror.\n<\/div>\n<p>\u00a0<\/li>\n<\/ol>\n<p><img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100423_1409_Week10SS2S11.png\" alt=\"\"\/><\/p>\n<p>\u00a0<br \/>\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0C\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0F\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0   P\u00a0\u00a0\u00a0\u00a0principal axis<\/p>\n<p>\u00a0<br \/>\n\u00a0<br \/>\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Concave mirror<\/p>\n<p>\u00a0<\/p>\n<ol>\n<li>\n<div>Convex mirrors \u2013 these mirrors bulge towards the incident light like he back of a spoon. Convergent mirrors are also referred to as divergent mirrors.\n<\/div>\n<\/li>\n<\/ol>\n<p>\u00a0<br \/>\n\u00a0<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100423_1409_Week10SS2S12.png\" alt=\"\"\/><\/p>\n<p>\u00a0<br \/>\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0C\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0P\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0   F\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/p>\n<p>\u00a0<br \/>\n\u00a0<br \/>\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Convex mirror<\/p>\n<p>\u00a0<br \/>\n\u00a0<strong>Terms used with spherical mirrors<br \/>\n<\/strong><\/p>\n<ol>\n<li>\n<div><em>The pole (p)<\/em> \u2013 this is the midpoint of the spherical mirrors\n<\/div>\n<\/li>\n<li>\n<div><em>The aperture<\/em> \u2013 this is the width or diameter of the mirror.\n<\/div>\n<\/li>\n<li>\n<div><em>The center of curvature (c) \u2013<\/em> this is the centre of the large sphere from which the spherical mirror is carved out.\n<\/div>\n<\/li>\n<li>\n<div><em>The radius of curvature (R)<\/em> \u2013 this is the distance between the center of curvature and the pole of the mirror.\n<\/div>\n<\/li>\n<li>\n<div><em>The principal axis<\/em> \u2013 this is the imaginary line passing through the pole (p) and the center of curvature (c)\n<\/div>\n<\/li>\n<li>\n<div><em>The principal focus (f)<\/em> \u2013 this is the point on the principal axis where the incident rays converges (for concave mirrors) or appear to diverge (for convex mirror)\n<\/div>\n<\/li>\n<li>\n<div><em>Focal length (f)<\/em> \u2013 this is the distance between the focus and the pole of the spherical mirror. It is always half of radius of curvature\n<\/div>\n<p>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0&#8212;4<br \/>\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0&#8212;5\n<\/li>\n<\/ol>\n<p><strong>Spherical aberration<br \/>\n<\/strong>This is the phenomenon whereby a spherical mirror of wide aperture cannot bring all parallel rays to the same focus. In other to avoid this, spherical mirrors of small aperture are usually used. This is also why parabolic mirrors are used in place of spherical mirrors in searchlights and car headlamps.<br \/>\n<strong>Construction of ray diagrams<br \/>\n<\/strong>The following tips are used in constructing ray diagrams<\/p>\n<ol>\n<li>\n<div>Light rays parallel to principal axis are reflected through the focus\n<\/div>\n<\/li>\n<li>\n<div>A light ray passing through the center of the curvature is reflected back along the same path\n<\/div>\n<\/li>\n<li>\n<div> A light ray passing through the focus is reflected parallel to the principal axis.\n<\/div>\n<\/li>\n<li>\n<div>Light rays striking the mirror at the pole is reflected such that the angle of incidence is equal to the angle of reflection\n<\/div>\n<\/li>\n<\/ol>\n<p><em>Characteristics of image formed by concave mirrors<br \/>\n<\/em><\/p>\n<ol>\n<li>\n<div>Object before center of curvature: the image formed is:\n<\/div>\n<\/li>\n<\/ol>\n<ul>\n<li>\n<div>same size the object\n<\/div>\n<\/li>\n<li>\n<div>between the center of curvature and the focus\n<\/div>\n<\/li>\n<li>\n<div>inverted\n<\/div>\n<\/li>\n<li>\n<div>real\n<\/div>\n<\/li>\n<\/ul>\n<ol>\n<li>\n<div>Object at the center of curvature: the image formed is\n<\/div>\n<\/li>\n<\/ol>\n<ul>\n<li>\n<div>same size the object\n<\/div>\n<\/li>\n<li>\n<div>at the center of curvature\n<\/div>\n<\/li>\n<li>\n<div>inverted\n<\/div>\n<\/li>\n<li>\n<div>real\n<\/div>\n<\/li>\n<\/ul>\n<ol>\n<li>\n<div>Object between the center of curvature and the focus: the image formed is\n<\/div>\n<\/li>\n<\/ol>\n<ul>\n<li>\n<div>Magnified\n<\/div>\n<\/li>\n<li>\n<div>Beyond the center of curvature\n<\/div>\n<\/li>\n<li>\n<div>Inverted\n<\/div>\n<\/li>\n<li>\n<div>real\n<\/div>\n<\/li>\n<\/ul>\n<ol>\n<li>\n<div>Object at focus: the image formed is\n<\/div>\n<\/li>\n<\/ol>\n<ul>\n<li>\n<div>Formed at infinity\n<\/div>\n<\/li>\n<\/ul>\n<ol>\n<li>\n<div>Object between focus and the pole: the image formed is\n<\/div>\n<\/li>\n<\/ol>\n<ul>\n<li>\n<div>Magnified\n<\/div>\n<\/li>\n<li>\n<div>Behind the mirror\n<\/div>\n<\/li>\n<li>\n<div>Virtual\n<\/div>\n<\/li>\n<li>\n<div>Erect\n<\/div>\n<\/li>\n<\/ul>\n<ol>\n<li>\n<div>Object at infinity: the image formed is\n<\/div>\n<\/li>\n<\/ol>\n<ul>\n<li>\n<div>Diminished\n<\/div>\n<\/li>\n<li>\n<div>Formed at the focus\n<\/div>\n<\/li>\n<li>\n<div>Real\n<\/div>\n<\/li>\n<li>\n<div>Inverted\n<\/div>\n<\/li>\n<\/ul>\n<p><em>Characteristics of image formed by convex mirrors<br \/>\n<\/em>The image formed by a convex mirror is always virtual, erect and diminished in size; it is formed between the pole and the principal focus. This is unlike the case of the concave mirror which can produce either real or virtual images that may be inverted or erect, magnified or diminished in size according to the position of the object.<em><br \/>\n\t\t\t<\/em><br \/>\n\u00a0<em>Linear magnification<br \/>\n<\/em>This is defined as the ratio of the image size to the object size<\/p>\n<p>\t\t\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0&#8212;6<br \/>\n<em>Mirror formula<br \/>\n<\/em>The focal length, <em>f<\/em>, object distance, <em>u<\/em>, and the image distance, <em>v<\/em>, can be related using the formula below:<br \/>\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0&#8212;7<br \/>\nFrom equation 6, we can have:<br \/>\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0&#8212;8<br \/>\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0&#8212;9<br \/>\nAlso, from equation 7, we can have:<br \/>\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0&#8212;10<br \/>\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0&#8212;11<br \/>\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0&#8212;12<\/p>\n<p>\u00a0Sign convention<br \/>\nThis is used to know and calculate by properly assigning sign to all the parameters used in mirror<\/p>\n<ol>\n<li>\n<div>The new Cartesian \u2013 here, all the distances measure to the left of the mirror from the pole are negative while distances measured to the right of the mirror from the pole are positive\n<\/div>\n<\/li>\n<li>\n<div>Real is positive and virtual is negative \u2013 this is the most widely accepted and used in calculations for mirrors and lenses. In this case:\n<\/div>\n<\/li>\n<\/ol>\n<ul>\n<li>\n<div>All distances are measured from the pole of the mirror to either left or right\n<\/div>\n<\/li>\n<li>\n<div>The distance of real objects and real images are positive\n<\/div>\n<\/li>\n<li>\n<div>The distance of virtual objects and virtual images are negative\n<\/div>\n<\/li>\n<li>\n<div>The focal length of a concave mirror is positive while the focal length of a convex mirror is negative\n<\/div>\n<\/li>\n<\/ul>\n<p><strong>Example<br \/>\n<\/strong><\/p>\n<ol>\n<li>\n<div>An object which is 5.0cm high is placed 10.0cm in front of a convex mirror of focal length 15.0cm. Find the position, size and nature of the image produced.\n<\/div>\n<p>Solution<br \/>\nUsing &#8220;real is positive&#8221;<br \/>\nGiven that f=-15cm, u=10cm\n<\/li>\n<\/ol>\n<p>\t\tFor magnification<\/p>\n<p>\t\tThus, the image is formed 6.0cm behind the mirror and the height 3.0cm. it is erect, virtual, diminished<\/p>\n<p>\u00a0<strong>CLASSWORK 10<br \/>\n<\/strong><\/p>\n<ol>\n<li>\n<div>(a) What do you understand by the term lateral inversion? (b) write your first name in block form to buttress (a)\n<\/div>\n<\/li>\n<li>\n<div>Differentiate between concave and convex mirror\n<\/div>\n<\/li>\n<li>\n<div>Two plane mirrors inclining at an unknown angle, forms 11 images. Find the value of the angle\n<\/div>\n<\/li>\n<li>\n<div>Mention three uses of plane mirrors\n<\/div>\n<\/li>\n<\/ol>\n<p>\u00a0<strong>ASSIGNMENT 10<br \/>\n<\/strong><strong>SECTION A<br \/>\n<\/strong><\/p>\n<ol>\n<li>\n<div>Which of the following abatement is true of virtual image (a) it is formed on the screen (b) it is formed by the intersection of actual rays (c) rays of light do not pass through it (d) all of the above (e) none of the above\n<\/div>\n<\/li>\n<li>\n<div>An object is placed between two plane mirrors inclined at 60<sup>0<\/sup> to each other. How many images will the observer see? (a) 6 (b) 5 (c) 4 (d) 3 (e) 2\n<\/div>\n<\/li>\n<li>\n<div>An object is place 15cm in front of a concave mirror of focal length 20cm, the image formed is (a) real, inverted and diminished (b) real, inverted and magnified (c) virtual, erect and diminished (d) virtual, erect and magnified (e) virtual, inverted and magnified\n<\/div>\n<\/li>\n<li>\n<div>A concave mirror can be used to produce can be used to produce a parallel beam of light if a light bulb is placed (a) between its focus and the pole (b) at its focus (c) at its center of curvature (d) between its focus and the center of curvature (e) none of the above\n<\/div>\n<\/li>\n<li>\n<div>When an image is formed in a plane mirror, the image formed will be (a) the same size as the object (b) smaller than the object  (c) laterally inverted (d) always virtual (e) all of the above\n<\/div>\n<\/li>\n<li>\n<div>Using the real is positive sign convention determine the sign of the focal length of a convex mirror (a) positive (b) negative (c) neutral (d) none of the above (e) options (a) and (b)\n<\/div>\n<\/li>\n<li>\n<div>An object is placed in front of a concave mirror of radius of curvature 12cm. if the height of the real image formed is three times that of the object, calculate the distance of the object from the mirror (a) 24 cm (b) 16 cm (c) 12 cm (d) 8 cm (e) 4 cm\n<\/div>\n<\/li>\n<li>\n<div>A magnified erect image four times the size of the object is formed by a concave mirror of focal length 12cm. what is the distance of the image from the pole of the mirror? (a) -36cm (b) -18cm (c) -24cm (d) -3.6cm (e) 24cm\n<\/div>\n<\/li>\n<li>\n<div>A boy walks away from a plane mirror at a constant speed of 5.0ms<sup>-1<\/sup> in a direction normal to the surface of the mirror. At what speed does his image move away from him? (a) 5.0ms<sup>-1<\/sup> (b) 2.50ms<sup>-1<\/sup> (c) 3.5.0ms<sup>-1<\/sup> (d) 1.25.0ms<sup>-1<\/sup> (e) 0.00ms<sup>-1<\/sup>\n\t\t\t\t<\/div>\n<\/li>\n<li>\n<div>The image of an object is located 6cm behind a convex mirror. if its magnification is 0.6, calculate the focal length of the mirror (a) 3.75 cm (b) 6.60 cm (c) 10.00 cm (d) 15.00 cm (e) 20.00 cm\n<\/div>\n<\/li>\n<\/ol>\n<p><strong>SECTION B<br \/>\n<\/strong><\/p>\n<ol>\n<li>\n<div>(a) Give the differences between real and a virtual image\n<\/div>\n<p>(b) A magnified, virtual image is formed 12cm from a concave mirror of focal length 18cm. calculate the position of the object and the magnification of the image\n<\/li>\n<li>\n<div>(a) Explain with the aid of diagram how the image of an object is formed by a plane mirror\n<\/div>\n<p>(b) State four characteristics of the image\n<\/li>\n<li>\n<div> (a) Define the following terms (i) principal focus (ii) radius of curvature (iii) principal focus\n<\/div>\n<p>(b) The screen of a pinhole camera is a square of side 160mm and it is 150mm behind the pole. The camera is placed 11m from a flag staff and positioned so that the image of the flag staff is formed centrally on the screen. The image occupies three-quarters of the screen. What is the length of the staff?<\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"<p>WEEK TEN LIGHT WAVES Light waves Source of Light waves Reflection of Light waves Reflection&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1,265],"tags":[],"class_list":["post-3315","post","type-post","status-publish","format-standard","hentry","category-posts","category-second-term-ss2-physics"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/posts\/3315","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/comments?post=3315"}],"version-history":[{"count":1,"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/posts\/3315\/revisions"}],"predecessor-version":[{"id":3316,"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/posts\/3315\/revisions\/3316"}],"wp:attachment":[{"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/media?parent=3315"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/categories?post=3315"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/tags?post=3315"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}