ime
b j e c b Nedle
Ctin)
ncedle W
Cthick)
concave mrror
Focal lenoth'of a
Date
Expt. No. PageNo. 25.
Ajn
Ajimt: To
lo nd
fnd the volue oy sor dfevent valuer o
.caA
incauef
ACOnCave merror 4o find the focal Lengh
[by platling Taph beoen u ) benen e H
ApparabuS
An opticokbench olth tre upr?5hts fzerd end ugTigt
fixed t0D 0der uprifhta_wlth lateral
COWcOve wTror A
Merror holder_, lWO movement)-
opticol yeedles
(one thin, 0ne thick) aknitino
Meter s cale neeolle ea half
Thedry
Aron wirror la
We hov2.
Wtv
ehere soca Lenth of concave mror
distann o tho 6hec neeole from_pole
the mror of
E dfstano e imaDe Meeodlle from
wirror pole of the
Nobe Accordind to thg on- epWention ue y
Medckiya alues. en have
Loes ebekve
Teacher's Signature
Date.
Expt.No. PageNo. 26
Procedure
o deterWMe rOugh focalLenfth
MOuNEhe ebncawe mirror n
Mount mirror holder
aGo Du in_the ope face the mlror tomrds
distan ree or building
8Obtai dhe imaße of the tran _or tne builking 0n_G-
whlte peinted üall screen) g_move tie wmirror forwarcd
boemord to easharp imape OM the Wal
AMe0sne e dietance betnen'the viror &the _Loo
LGrean) i s wil he_equal io roush foco Lenbih +
ToSet the mrror
Place xed uprilgh year Xern ead o Hhe optieal htlnch 4
|the two other uprioht oih laieral yOvement)near the
other end
6:Clap the_holder uot viirror n he xed upright
Keepin wirror ao toaards Dther end ot the benchh
utace perpendicular o is lenoth
Make mirror urface vorioal usnLevellin SLNens_O
Hie pptfcal oench fin final adjustment the_princephl
axiS_ O the mirro MusE h2 horlzentol paralelto
HAe optical hench)
3Note ie pos?tion. h e index u4ark o the hase o
wirror _uprlsut
o se the oo'ech yeecdle
ake he thinopttca YeDCle as oblect_Meedle fo)
MOunh_i in secovd upiohm
lOMove the olheek Meedke Uriðht a clamD Piat a
dietance [in ful e eorlL
J Elme the abtatned
Teacher's Signature
Date
Expt. No. Page No. 2ZE_
rougw -foco lenbtw bhe WYYOY
1 epz eyeelosed se lth the_6u eye.open _from the
Dther _end he aphical bench A nveried_"eylarfed image.
Ahe ende tip_wl he sann ip of the. nafe must
e fhe middde o the_mrror ( mafie s nni sen4
MOve 6biect needle uprlsht_anay fnm ihe wiyror
NoteNote the positiDW the ndea mark o the hase C
the obiect hedle miiht
To setAhe imaß e needle
Ment the thik optical neaclle_(mafe neacle)n thd
uprtonE movethe uprisWE_near thë other end of the
opticol bench_
Adust the heio of the mafe neecle so that ts tip is
Secn n _Lne wtth the tlp ofthe mafe ohenSen wit
rt6 open eye
16 Move the eye tovwards rioht.The trs wil bel separated The
twage tip the tmaeyeedle tip have poyalax_
PRemovehe parolax as deicribed,.The parallax betomes
H
remove d tip to tip
Ik Nate ha polHon e the nder monk on the hae e #he
iMaeMeecile wpripuk-
19 Read a the posions 0 the dex marks bn the table
dhai'nst obeervaaion 2
1delermine_indexcoTrectlon
10 Fnd ndex eO1rechionor distance helucen_polemlrro &_
ip of_the ehieck yerdle e also for distance beiueen pole
mirror e p_the lmaho Meedle _as decribed
Tem to et observation 2 £1_REpeat_the experMe
Teacher's Signature.
Graph beuonn ue v
Date
Expt. No.
Page No. 2 8
28 Move ooect
3Move neecile uprlht qway from irror in stepi
| lcw to et obeervoion 4,5E6.Repeat
08 Recovd a the obeervatlov, the experment
|Observation
Rowb OCa len6thy of the 6ve eoncaye mivror =20cm
Actua lenbta ofthe kluin yeedle 2Lm
Obeerved dllstanco betweoM Ehe mirror a obfect yeee LoheN
kwing yeedle le_placecd b ehwee, tluen y
incle eoYecHtonfar tho olbloek cliztnndCes
4 NoPoeilon_ ohtrvedcorrecked foco
obs0bfeck (Ew distane eLPe tane tenoh
Leelle
ACm) Cem) m_ CCm) Cam)
100 a5 |100 00 O-0) 20OD
28 21 4 28 00%pO12016
20 0 61|6023 O:014 201D
5
9.22 49 292 48
2A0020 2000
Teacher's Signature.
Graphotoo
Date
Expt.No. Page No. 29
Caleulakions
Calczalations of focal length by_1aphieal mthods
u-V 4raphr 4eleot_o ultoble but thee same 6Caleto
reprrAehb u alongx'-axls &valomg_y-axk
Actorckn to AON_conventtons, ln this'coAe u G V
lp0th are vo Plot the varfous_point e_for aiffeTenE
Sehs Of Yaue s opu y fTom_the_ohservation table_
he uaph eomPA but to be a rectangular
ADArh0la
Dth Rne 0A Making_an ndle 4 oith elther ax
e,e hieectfng (Y'ox')meettnÙ the eurve at po?nkA
DrRAD A e AD _perpinckeular 0n e axes rupectively
The value of u e y_w?u be same for poinb A the
Cnoncinate of paint A_must be (2f,1) becaus fora
AOncav2 meror u i v ane equai only when_ohfect i
_ptacod at_the_centre of cuTvaure,
Henca
Explanahion
Frovn buirorformula applled fo _poln- 4
LL 0TVL
2
0 2Oem
Teacher's Signature
Graph bebwen u v
Date
ExptNo Page No. 20
TY Wruph:A Gultuble but the _seale _selected too
r e p r e s £V olon -axi e n alona Y-ans Dy sro.
wow -ve 4is tve the vartous vaMes ATe oiven
n the ObgervuiO table the. ruph comes owb tO be
ckralohb_tPne
ghe simi5ht line cuts the t0D_are_Ox'e orat an angle
4g at poniS_PeQ4rupectfvely Q making equal_nieTCep:E
hen focoul leng,f Cm
Auobher u-v oraphi A_auitoble but the same scale fe
Aelected 6 Teprestnt u_along_a-axise v along Y-axk1uo
powts_aFdkstanNy_CLUa Ua efc are marked alondthe
ox'-axis e the correpOnding_poni at_distanee V,^V2,V>te
Ore yAarleee alouo oy.axk oY drferent gek 0f_observaton,
Core clrouon Thee lmea mieyecb_al pont b_au shoon ?n
te rap
KLP KNLperpendiculats 0re dra1 to x L fax?s
mpeckvel4
Relk
The focaenglh o the gen eonv lens as
delkrm'ned from
focd Lengh Om tL-v
-V) Yaph : 0cm
a p h z lom
Teacher's Signature,
Date
Expt. No. Page No. -
TeCawlonS
Tp t0 tip paraax hould be removeo bebween the yeedle 1
imaie the Merdle 0_
2The prihwts 4ould be vertical
2ImdexCOÝYeciiow for y shauld be apped
SOwrces 0f errors
1he upöts mo4 ot be the vertical
2 Porallkzremoval May not be perkek
Guomlthed bu_
Lnas uchdrtta Rath
Teacher's Signature.
