ikB ;kstuk d{kk & VIII fo"k; & foKku v/;k; &ySUl English

mn~ns’; &  Kku&fo|kFkhZ ySUl ls lEcfU/kr rF;ksa dks le> ldsxsaA fo|kFkhZ ySUl dh cukoV] ySUl ls lEcfU/kr ifjHkk"kk,sa,oe~ izfrfcEc cuus dh izfØ;k tku ldsxsaA  vocks/k& fo|kFkhZ vilkjh,oe~ vfHklkjh ySUl esa vUrj dj ldsxsaA  Kkuksi;ksx&-fo|kFkhZ vilkjh,oe~ vfHklkjh ySUl ls lEcfU/kr midj.kks dk iz;ksx djus esa vius Kku dk mi;ksx dj ldsxsaA  dkS’ky& fo|kFkhZ ySUlksa ls oLrqvksa ds izfrfcEc insZ ij izkIr dj ldsxsaA fo|kFkhZ ySUlksa ls ds izfrfcEc cuus dh izfØ;k dks fp=ksa ds ek/;e ls iznf’kZr dj ldsxsaA  vfHk:fp& fo|kFkhZ ySUlksa ls lEcfU/kr rF;ksa dks i= if=dkvksa esa i<us esa :fp ysxsaA  vfHko`fr& fo|kFkhZ vius vklikl ds ifj{kS= esa miyC/k midj.kkas esa ySsUl ls lEcfU/kr rF;ksa dk mi;ksx dj ldsxsaA visf{kr O;ogkjxr ifjorZu English

ifjHkk "kk  dksbZ ikjn’khZ ek/;e tks nks i`"Bksa ls f?kjk gks ftuesa,d i`"B oØ gks] ySUl dgykrk gSA English

ySUl nks izdkj ds gksrs gSa ySUl tks chp esa ls eksVk o fdukjksa ls iryk gksrk gS mls mŸky ySUl dgrs gSaA mŸky ySUl ij vkifrr fdj.ksa viorZu ds Ik’pkr~ vfHklkfjr gks tkrh gSaA blfy, bls vfHklkjh ySUl Hkh dgrs gSaA ySUl tks chp esa ls iryk o fdukjksa ls eksVk gksrk gS mls vory ySUl dgrs gSaA vory ySUl ij vkifrr fdj.ksa viorZu ds Ik’pkr~ vilkfjr gks tkrh gSaA blfy, bls vilkjh ySUl Hkh dgrs gSaA mŸky ySUl vory ySUl English

mŸky ySUl ds izdkj leŸkyks Ÿky voŸkyks Ÿky mŸkyk sŸky English

vory ySUl ds izdkj leŸkyks oŸky mŸkyk soŸky voŸkyks oŸky English

oØrk dsUnz ySUl oØ i`"Bksa ls feydj cuk gksrk gSa bu oØ i`"Bksa ds dsaUnz c o c’ ySUl ds oØrk dsaUnz dgykrs gSaA C.C’. English

eq[; v{k,d lh/kh js[kk AB tks oØrk dsUnzksa ls xqtjrh gSa eq[; v{k dgykrh gSA C’.C. C’. English

izdkf’kd dsUnz ySUl dk dsUnz fcUnq O izdkf’kd dsUnz dgykrk gSA O O English

mŸky ySUl dk Qksdl fcUnq eq[; v{k ds lekukUrj vkifrr izdk’k dh fdj.ksa mŸky ySUl ls viorZu ds Ik’pkr fcUnq F ls xqtjrh gSaA fcUnq F mŸky ySUl dk Qksdl fcUnq dgykrk gSA mŸky ySUl dk Qksdl fcUnq okLrfod gksrk gSA O F F English

vory ySUl dk Qksdl fcUnq eq[; v{k ds lekukUrj vkifrr izdk’k dh fdj.ksa vory ySUl ls viorZu ds Ik’pkr vilkfjr gksrh gSa vkSj fcUnq F ls vkrh gqbZ izrhr gksrh gSaA fcUnq F vory ySUl dk Qksdl fcUnq dgykrk gSA O F English

Qksdl nwjh ySUl ds izdkf’kd dsUnz,oe~ Qksdl fcUnq ds chp dh nwjh dks Qksdl nwjh dgrs gSA English

ySUl {kerk ySUl dh Qksdl nwjh ds O;qRØe dks ySUl dh {kerk dgrs gSaA ;fn ySUl dh Qksdl nwjh ehVj esa gks rks ySUl dh {kerk dk ek=d Mk;IVj gksrk gSA vfHklkjh ySUl dh {kerk /kukRed o vilkjh ySUl dh {kerk _.kkRed gksrh gSA English P = 1/f Mk;IVj

Xkksyh; /kjkry ls viorZu ds fu;e 1- tc izØk’k dh fdj.k eq[; v{k ds lekUrj vkifrr gksrh gSa rks mŸky ySUl esa viorZu ds i’pkr~ eq[; Qksdl ls xqtjrh gSa rFkk vory ySUl esa eq[; Qksdl ls vkrh gqbZ izrhr gksrh gSaA FF OO English

Xkksyh; /kjkry ls viorZu ds fu;e F F 2- tc izØk’k dh fdj.k ySUl ds eq[; Qksdl ls gksdj tkrh gS ;k tkrh gqbZ izrhr gksrh gSa rks viorZu ds Ik’pkr eq[; v{k ds lekukUrj gks tkrh gSA O O English

Xkksyh; /kjkry ls viorZu ds fu;e 3- ySUl ds izdk’k dsUnz o ls tkus okyh izdk’k fdj.k fcuk eqMs gh lh/kh fudy tkrh gSA O O O English

Xkksyh; /kjkry ls viorZu ds fu;e tc izdk’k dh fdj.k eq[; v{k ds lekUrj vkifrr gksrh gSa rks mŸky ySUl esa viorZu ds i’pkr~ eq[; Qksdl ls xqtjrh gS rFkk vory ySUl esa eq[; Qksdl ls vkrh gqbZ izrhr gksrh gSA tc izdk’k dh fdj.k ySUl ds eq[; Qksdl ls gksdj tkrh gS ;k tkrh gqbZ izrhr gksrh gS rks viorZu ds Ik’pkr eq[; v{k ds lekukUrj gks tkrh gSA ySUl ds izdk’k dsUnz o ls tkus okyh fdj.k fcuk eqMs lh/kh fudy tkrh gSA English

mÙky ySal ls izfrfcEc fuekZ.k

Tkc fcEc vuUr ij gks mŸky ySUl ls izfrfcEc Qksdl fcUnq F ij cusxkA O F English

Tkc fcEc 2F ds ihNs gks Tkc fcEc 2F ds ihNs gks mŸky ySUl ls izfrfcEc Qksdl fcUnq F vkSj 2F ds chp cusxkA F2F F O English

Tkc fcEc 2F ij gks 2F F F O mŸky ySUl ls izfrfcEc 2F ij cusxkA English

Tkc fcEc F vkSj 2F ds chp gks F2F F O mŸky ySUl ls izfrfcEc 2F ds ihNs cusxkA English

Tkc fcEc F ij gks mŸky ySUl ls izfrfcEc vuUr ij cusxkA F2F F O English

Tkc fcEc F vkSj izdk’k dsUnz O ds chp gks mŸky ySUl ls vkHkklh izfrfcEc ySUl ds ihNs cusxkA O F2F F English

mŸky ySUl ls cuus okys izfrfcEc dh fLFkfr] izd`fr,oe~ vkdkj fcEc dh fLFkfr izfrfcEc dh fLFkfr izfrfcEc dh izd`fr izfrfcEc dk vkdkj vuUr ij F ijokLrfod fcUnqor~ vkdkj dk 2F ds ihNs F vkSj 2F ds chp okLrfod vkSj mYVk oLrq ls NksVk 2F ij okLrfod vkSj mYVk oLrq ds cjkcj F vkSj 2F ds chp 2F ds ihNs okLrfod vkSj mYVk oLrq ls cMk F ijvuUr ij okLrfod vkSj mYVk oLrq ls cMk F vkSj ySUl ds chp ySUl ds iwoZ vkHkklh vkSj lh/kk oLrq ls cMk English

vory ySUl ls lnSo vkHkklh izfrfcEc Qksdl vkSj ySUl ds chp curk gSA O F2F O F O F O F English

Lkkj k’ka geus yksxksa dks p’esa] lw{en’khZ] nwjn’khZ vkSj dsejs esa ySUlksa dk mi;ksx djrs ns[kk gSA vc ge le>rs gSa fd bu midj.kks esa ySUlks dk mi;ksx fdl izdkj fd;k tkrk gS rFkk mŸky vkSj vory ySUl ls izfrfcEc dSls curk gSA lkFk gh bl v/;k; esa geus ySUlksa ls lEcfU/kr ifjHkk"kkvksa,oe~ xksyh; /kjkry ls viorZu ds fu;eksa dks le>k gSA English

vH;kl iz’u

Tkc fcEc F ij gks mŸky ySUl ls izfrfcEc vuUr ij cusxkA F2F F O

lgh fodYi dk p;u djsa iz1& mÙky ySal ds Qksdl fcanq F ij j[kh oLrq dk izfrfcEc cusxk & F o 2F ds chp esa vuUr ij F ij 2F ij

lgh mÙkj mÙke vxyk iz’u

iqu% iz;kl dhft, vxyk iz’u nksgjku djsa

vory ySUl ls lnSo vkHkklh izfrfcEc Qksdl vkSj ySUl ds chp curk gSA vory ySUl ls lnSo vkHkklh izfrfcEc Qksdl vkSj ySUl ds chp curk gSA O F2F O F O F O F

lgh fodYi dk p;u djsa iz2& voÙky ySal ls lnSo izfrfcEc cusxk & vkHkklh o mYVk okLrfod o lh/kk okLrfod o mYVk vkHkklh o lh/kk

lgh mÙkj mÙke vxyk iz’u

iqu% iz;kl dhft, vxyk iz’u nksgjku djsa

ySUl {kerk ySUl dh Qksdl nwjh ds O;qRØe dks ySUl dh {kerk dgrs gSA ;fn ySUl dh Qksdl nwjh ehVj esa gks rks ySUl dh {kerk dk ek=d Mk;IVj gksrk gSA vfHklkjh ySUl dh {kerk o /kukRed o vilkjh ySUl dh {kerk _.kkRed gksrh gSA P = 1/f Mk;IVj

lgh fodYi dk p;u djsa iz3& ySal dh {kerk dk ek=d gksrk gS& dSyks jh ehVj MkW;I Vj yhVj

lgh mÙkj mÙke vxyk iz’u

iqu% iz;kl dhft, vxyk iz’u nksgjku djsa

Qksdl nwjh ySUl ds izdkf’kd dsUnz O,oe~ Qksdl fcUnq ds chp dh nwjh dks Qksdl nwjh dgrs gSA

lgh fodYi dk p;u djsa iz4& ySUl ds izdkf’kd dsUnz,oe~ Qksdl fcUnq ds chp dh nwjh dks dgrs gS& odzrk f=T;k fcEc nwjh izfrfcEc nwjh Qksdl nwjh

lgh mÙkj mÙke vxyk iz’u

iqu% iz;kl dhft, vxyk iz’u nksgjku djsa

mŸky ySUl dk Qksdl fcUnq eq[; v{k ds lekukUrj vkifrr izdk’k dh fdj.ksa mŸky ySUl ls viorZu ds Ik’pkr fcUnq F ls xqtjrh gSaA fcUnq F mŸky ySUl dk Qksdl fcUnq dgykrk gSA mŸky ySUl dk Qksdl fcUnq okLrfod gksrk gSA O F F

fjDr LFkkuksa dh iwfrZ djsa & iz5&vfHklkjh ySUl dk Qksdl gksrk gS& vkHkkl h okLrfo d

fjDr LFkkuksa dh iwfrZ djsa & iz5&vfHklkjh ySUl dk Qksdl gksrk gS& vkHkkl h okLrfo d

vxyk iz’u lgh mÙkj mÙke

iqu% iz;kl dhft, vxyk iz’u nksgjku djsa

Tkc fcEc 2F 2F ij gks 2F F F O mŸky ySUl ls izfrfcEc 2F ij cusxkA

fjDr LFkkuksa dh iwfrZ djsa & iz6& tc oLrq vfHklkjh ySUl ls 2f nwjh ij gks rks mldk izfrfcEc ySUl ls nwjh ij curk gSA 2f vuUr

fjDr LFkkuksa dh iwfrZ djsa & iz6& tc oLrq vfHklkjh ySUl ls 2f nwjh ij gks rks mldk izfrfcEc ySUl ls nwjh ij curk gSA 2f vuUr

lgh mÙkj mÙke

iqu% iz;kl dhft, lekIr nksgjku djsa

izLrqrd ŸkkZ ujsUnz dqekj xqIrk v/;kid jkekfo fnokdjh] mejS.k vyoj ¼jktLFkku½ English

Lesson Plan Class :- VIII Subject :- Science Topic:- Spherical lenses fgUnh

Knowledge:- The students would be able to recall the fact about the Spherical Lenses i.e. structure, definition, process of building images. Understanding:-The students could difference between the convex and the concave lenses. Application:-The students would be able to use their knowledge to use those devices related to convex and concave lenses. Skill:- The students would be expert in getting an images through lenses and presenting this process by figures. Interest:-The students would take interest in reading the facts about the spherical lenses into the magazines and newspapers. Objectives:- Expected behavioral changes fgUnh

Any transparent material bound with two surfaces of different curvature form a lens. Definition fgUnh

Concave lens :-A parallel beam of light incident on a concave lens diverges after refraction, it is therefore also known as diverging lens. The lenses are divided into two classes. Convex lens :- A parallel beam of light incident on a convex lens converges after refraction, it is therefore also known as converging lens. fgUnh

Some common shapes of convex lenses Convex or Double convex Planoconvex Concavo convex fgUnh

Some common shapes of concave lenses Concave or double concave Plano concave Convexo concave fgUnh

C.C’. Centre of curvature Lenses are made of spherical surfaces. Centre of these surfaces C and C’ are called centre of curvature. fgUnh

C’.C. C’. Principal axis A straight line AB passing through the centres of curvature C and C’ is called the principal axis. fgUnh

O O Optical centre The centre point O is called the optical centre of the lenses. fgUnh

O F F Focus of a convex lens All the rays parallel to principal axis falling on convex lens, pass through a point F after refraction. The point F is called the focus of convex lens. Focus of convex lens is real. fgUnh

O F All the rays parallel to principal axis falling on concave lens diverge after the refraction. These rays appears to diverge from the point F. The point F is called the focus of concave lens. Focus of a concave lens fgUnh

Focal length The Distance between optical centre of the lens and its focal point is known as the focal length of lens. fgUnh

LENSE POWER Reciprocal of focal lenth of lense is called Lense Power. P = 1/f Dipter fgUnh

FF OO Rules of refraction through spherical surfaces 1. The ray parallel to the principal axis, passes through the focus in convex lens and appears to diverge from the focus after refraction in concave lens. fgUnh

F F O O Rules of refraction through spherical surfaces 2. The ray passing through the focus or directed towards it become parallel to the principal axis after refraction. fgUnh

O OO Rules of refraction through spherical surfaces 3.The ray passing through the optical centre of the lens, goes undeviated. fgUnh

Therefore rules of refraction through spherical surfaces are The ray parallel to the principal axis, passes through the focus in convex lens and appears to diverge from the focus after refraction in concave lens. The ray passing through the focus or directed towards it become parallel to the principal axis after refraction. The ray passing through the optical centre of the lens, goes undeviated. fgUnh

O F When the object is at infinity Image formed by a convex lens is at focus point. fgUnh

F2F F O When the object is placed beyond 2F Image formed by a convex lens lies between F and 2F. fgUnh

2F F F O When the object is placed at 2F Image formed by a convex lens is at the same distance means 2F. fgUnh

F2F F O When the object is placed between F and 2F Image formed by a convex lens is beyond 2F. fgUnh

F2F F O When the object is placed at F Image formed by a convex lens is at infinity. fgUnh

O F2F F When the object is placed between F and the optical centre O Virtual Image formed by a convex lens is on the same side of the lens as the object. fgUnh

Position, Nature and Size of the image of an object formed by a Convex lens Position of the object Position of the Image Nature of the Image Size of the image At infinityAt FRealPoint image Beyond 2FBetween F and 2FReal and invertedSmaller than the object At 2F Real and invertedSame size as the object Between f and 2FBeyond 2FReal and invertedLarger than the object At FAt infinityReal and invertedVery large than the object Between f and the lens On the same side as the object Virtual and erectLarger than the object fgUnh

O F2F F Image formed by a concave lens Image formed by a concave lens is always virtual irrespective of the position of the object. fgUnh

Conclusion We might have seen people using lenses in the devices like spectacles, microscopes, telescopes and cameras. Now we know why lenses are used in these devices and how images are formed by convex and concave lenses. Through this topic we also learn about the definitions related to spherical lenses and rules of refraction through spherical lenses. fgUnh

EXERCISE

F2F F O When the object is placed at F Image formed by a convex lens is at infinity.

Choose the right answer- Q1- When the object is placed at F image is formed by convex lens- Between F and 2F Infinity On F On 2F

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O F2F F Image formed by a concave lens Image formed by a concave lens is always virtual irrespective of the position of the object.

Choose the right answer- Q2- Image formed by Concave Lens- Real and inverted Virtual and inverted Real and erect Virtual and erect

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LENSE POWER Reciprocal of focal lenth of lense is called Lense Power. P = 1/f Dipter

Choose the right answer- Q3 - Unit of lens power is - Dipter Liter Meter Calorie

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Focal length The Distance between optical centre of the lens and its focal point is known as the focal length of lens. fgUnh

Choose the right answer- Q4 - The Distance between optical centre of the lens and its focal point is known as- Focal Lenth Image Distance Object Distance Radius of curvature

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O F F Focus of a convex lens All the rays parallel to principal axis falling on convex lens, pass through a point F after refraction. The point F is called the focus of convex lens. Focus of convex lens is real.

Fill in the blanks- Q5 - Focus of concave lens is ……… Virtual Real

Fill in the blanks- Q5 - Focus of concave lens is ……… Virtual Real

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2F F F O When the object is placed at 2F Image formed by a convex lens is at the same distance means 2F.

Fill in the blanks- When the object is placed at 2F Q6 - When the object is placed at 2F Image formed by a convex lens is at ………… F 2F

Fill in the blanks- When the object is placed at 2F Q6 - When the object is placed at 2F Image formed by a convex lens is at ………… F 2F

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Presented by Narendra Kumar Gupta Teacher Govt. Secondary school, Diwakari Alwar, Rajasthan India fgUnh