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9. Ray Optics, Ray + Ray Optics -, ray oflight is the straight line path, going foom one "point to another., the geometry, straight liles 'to represe nt macooscopic phenomena, reflection,'refraction etc, A, followed by lignt" in, The ray optics therefore uses, et,, like rectilinear poopagatton, gascopic, o, Reflection of Light -, Reflection is the phenomena of change in, light without, A smooth and well polished surface which, the path of any change inº medium., Mirror-, reflects re, colled aaey most of the falling on, light, a mirror., normal, N!, A,, nomal, incident, ray, reflected, ray, angle of angle of, incidence reflection, M1 T, M2, miTor surace, In, figure MIM2 is a plane mior., Ą ray D, L AON=, light fll, is U called, ls, on, the minror along., incidlent, AO, at, called, roay and i is callid amgle of, ay: cormai to the mirror at o., normal to the minor at ó., mgle.of, incidence, where ON, Incident ray, It is caled reflected ray amd, angle of reflection., is reflected along, OB at L NOB, r is Known as, and', Scanned with CamScanner
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Laws of reflection -, (i) of incidence is equal to angle of reflection., Angle, Li, (1i) Incident ray (OA), reflected rau COB) amd normal, CON) to the mirror, all'lie in the same plane, yoy, Spherical Mirrors, a part of a hollow, and other side, sphere, whose one side is reglecting amd'other side, A spherical, whose ome, minror is, is opaque., There are two types, (1) Concave, of, spherical mirrors, mirror -, cohose reflecting surface is, towards the centre of the sphere of Shich the miror, is a part., As shown e Ca), in tigur, ure, M1, M., P, P, M2, M2, -R, a, (2) Convex mirror -, cwhose reflecting surface is, away foom the sentre, mirrbr, of, the spharre df which the, is a part . As Shown, shown 'in tiquie (6)., Some Important Terms -, li) Centre of curvature (c) -, The centre of, the sphere of which the miror, forms a part is, called the' Centre of.cuvature., It. is repsesented, c'., lii) Radius of curvature (R)-, The radius of the, ijo, sphare, called 'the radius ok curvature, of. which the, mirror forms, a part, of the spherical mirror-, It is'repesented by 'R'., Scanned with CamScanner
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(ii ) Vertex or Pole-, The middle point or centse of the spherical, mirror is called vertex or pole of the mirron., It is rephesented by P., liv) Aperture of the mirror, The diameter M,M2 .of the spherical miroY, dlinear aperture of the mirror., is called aperture, (V) Angular, aperture, The angle M,CM2 , c by the, subtended at, by the dliameter, angular aperture., (vi ) Principal axis -, of the spherical mior is caled, The straight line joining, centre of curvature of spherical mirror extended on, both sides is called principal axis of the miror., the pole and the, (vii) Principal section-, plane parsinga thoough, of the miois called princi pal, mirror., A section of the spherical mino cut by a, pole amd centre of cuu&ture, the, section of, (vii) Principal focus (F)-, It is a point on the principal axis of, the mirror at cwhich rays icident on the minor in, a direction paralled to the principal axis actually, meet or aPpear, mirror., to diverge after reflection foom the, * In case of a comvex mirror ,, wherefoom the says after reflection appear to diverge., of a Convex minror, E is a rirtual, * In, Concave mior F is a real pint, Case of a, where the ays after reftection from the miror, actually meet., Scanned with CamScanner
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(3) The h Lincipal axis of the mirror are taken positive, Concave miror, Convex mimor, Principal axis, P, Principal axis, P, Focal, Focal, length, Tength, The distamce of principal focus F from the pole P, of the spherical mišror is 'callid focal' length (f) of, the mimor., PF = f, New Cartesian sign Conventions -, (1), All the distances, are measuured from, pole LP) of, spherical rimior., (?) The dis tances measured, of light are taken as pasitive and the distances, measured in a direction'opposite to the direction of, incidence oB light, the direction.ok. incidence, as negative., are, (3) The heights measured upwards and perpendiculas, to the pLincipal axis ot the miror are taken positive, and the heights, negati, measured, downwards are taken as, ire., Object on the left, м, Direction of, incident light, Height, upwards, (+vc), Distance towards, Distance towards, the left (-ve), the right (+ve), P, X, в, B', Height, downwards (-ve), A', Mirror, N, Scanned with CamScanner
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Relation between f amd R, (a) Concave Mirror, A-, R/2, F, of, -R-, minor is, equal to, The focal length. of a, half the radius of čurvature of the mirror., concave, (b) Convex Mirror, .N-, A-, of, P, R-, miror is equal to half, Focal Length of, of its radius, a convex, %k Curvature., obo, Some Important Rules, F, (a), (b), P, (C), Scanned with CamScanner
