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--| KEYWORDS ~ ~ EXPLANATIONS AND MEANINGS |---3, , 1,, , ”, , we, , Curved Surface, , _ Angle of incidence (AI), , Angle of reflection (Zr):, , Normal, , . Centre of curvature (C), . Radius of curvature (R), , » Principal axis (or), , Central axis, , » Pole (P) (or) Vertex, : Focus or focal point (F), , ' Focal length (f), * Object distance (u), , * Image distance (v), , The surfaces which are not flat are called curved surfaces. |, , The angle between incident ray and normal is called angle J, of Incidence,, , The angle between normal and reflected ray is called, angle of reflection,, The line perpendicular to the surface is called normal., , The normal from a concave mirror converges at a point,, that point is called centre of curvature., , called radius of curvature., The horizontal line which passes through the centre of, , curvature and pole., , I, I, I, I, I, I, I, The distance between vertex and centre of curvature is |, I, I, I, I, The point where central axis touches the mirror., , I, , The rays coming from distanct object parallel to concave, mirror will converge at a point called focus or focal point. I, , The distance between vertex and focus. i, The distance between object and mirror is called object, , distance., The distance between image and mirror is called image |, , distance. I

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Real image, Ray diagram, , Magnification (m), Reflection, , Incident ray, Reflected ray, , Virtual image, , Spherical mirror, Concave mirror, , Convex mirror, , ., , Tie re,, , Fe Se et ee Se AE dS YD Se SOR Se ee me es, , Virtual image, , The image formed in mirror by extending the rays backwards |, is called a virtual image. |, , The image formed due to converging of light rays is real image, |, A diagram showing the paths of selected rays through an |, optical system. ;, Ratio of size of image to size of object. |, The bouncing back of light is called reflection. |, The ray which is incident on a surface is called incident ray. |, The ray which is reflected from the surface is called reflected, ray. |, Virtual image is the image formed due to diverging of light rays. |, (oR) |, , I, , I, , |, , The image formed due to extension of rays in backward, direction., , A mirror which has curved reflective surface is spherical |, , mirror. |, A spherical mirror whose reflecting surface is curved inwards, is called concave mirror., , A spherical mirror whose reflecting surface is curved |, outwards is called convex mirror. I

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x [tis easy to understand the certain properties of light by draw a ray diagram., __——, , , , , , , , , , , , , , , , x| Position of Position of the Enlarged? / Erected/| Real /, the (object) image _—|_— Diminished? | Inverted | virtual, Between mirror & F Behind the mirror Enlarged Erected Virtual, On focal point At infinity High enlarged | Inverted |. Real, Between F and C Beyond C Enlarged Inverted Real, On centre of curvature} OnC Same size Inverted Real, Beyond C Between F andC | Diminished inverted Real

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ey.W mth, , , , , , , , , , , IMPROVE YOUR LEARNING, , , , (CONCEPTUAL UNDERSTANDING Gy, , 1. "Laws of reflection of light are not applicable to curved surfac oe, A. No, laws of reflection of light are applicable to curved surfaces also., 2. How do you find the focal length of a concave mirror 2?, (OR), What is the name given to distance between pole and focal point ? How would you, able to find that distance by using an activity ? That distance is called focal length,, A. To find the focal length of a concave mirror —, , 1) Hold a concave mirror perpendicular to the, direction of sunlight., , es" Is it correct?, , 2) Take a small paper and slowly move it in front, of the mirror and find out the point where you, get smallest and brightest spot, which is image, , of the sun., 3) The rays coming from sun parallel to the, concave mirror are converging at a point., , 4) This point is called Focus or focal point (F) of the concave mirror., , 5) Measure the distance of the spot from the vertex (Point P) of the mirror., 6) This distance gives the focal length of the concave mirror., 3. Where will the image form when we place an, concave mirror at a point between focus and ce., A. 1) When we place an object on the Principal ax, , concave mirror at a point between focus and, of curvature then the ima, the centre of curvature., , 2) The image is enlarged, inverted and real., 4. Find the distance of the i, distance of 10 cm in fron, , , , , , , , object, on the principal axis of a, ntre of curvature ?, is of a, , centre, ge will form at a Point beyond, , , , , , , , , , mage, when an object is lace axis at 4, ge, . 2 Pp d on the Principal i, tofa concave mirror whose radi Vv: is 8 cm, ; ius of cur ature @, , A. Object distance u = — 10 cm, , Radius of curvature (R) = ~g cm, , “. Focal length ¢ = x. 38, , 9t Physical Science, , =-4cem

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yi, , A., , Mirror formula : t, , Image distance v =?, , 1 1, , -. The image distance = 6.67 cm., , , , , , = — 6.67 cm., , i.e.. Real image is formed at same side of the mirror., , State the differences between convex and concave mirrors., CR), Distinguish between convex and concave mirrors., (COR), Ramu observed a mirror which is used by drivers to see the vehicles behind. Srinu, observed a mirror which is used by dentist to see teeth inside the mouth. What are, those two mirrors and distinguish them ?, , Those mirrors are (1) Convex, (2) Concave, , , , , , , , , , , , , , , , , , , , | Convex mirror Concave mirror, , | 1. After reflection from the mirror the 1. After reflection from the mirror, , | light rays diverge. | the light rays converge., , | 2. The reflecting surface curved 2. The reflecting surface curved, , | outward. inward., , | 3. Radius of curvature and focal length are | 3. Radius of curvature and focal length are, | taken as Positive, in sign conversion. taken as negative, in sign conversion., | 4. It's magnification is positive only. 4. It's magnification may be both positive, i and negative., , | 5. Magnification of convex mirror is in 5. Magnification value of concave mirror, | between zero and one. having all values., , 6. The image formed due to convex 6. The image formed due to concave, , | mirror is always virtual. mirror is generally real. But when, an object placed between vertex and, | focus it is virtual., , | 7. The image formed due to convex 7. The image formed due to concave, , | mirror is always diminished. mirror is diminished or magnified, , | or same size based on position of object., | 8. The image due to convex mirror is | 8. Generally the image is inverted, , | always erect. except when the object is placed, , , , between P and F., , , , , , (PBN OO Drostaat Gatanne