256735977 Physics Investigatory Project

PHYSICS INVESTIGATORY PROJECT

ABHISHEKVASHISHTH

CLASS-XII-D ROLL NO: 2015-2016 KENDRIYA VIDYALAYA NO.1  JAMNAGAR

I deeply acknowledge my !nce"e #$ank #o my p$y!c ACKNOWLEDGEMENT #eac$e" M! So%m! &ane"'ee

(o" $e" g%!dance and ad)!ce #o comple#e my p"o'ec# %cce(%lly a well a (o" p"o)!d!ng me all #$e (ac!l!#!e #o *n!$ #$e p"o'ec# on

 

CERTIFICATE

NAME : NILAN,ANA MISH-A c!ence

CLASS : .I

ROLL NO. : /0 INSTITTION: KENDRIYA VIDYALAYA IIMC JOKA

This is certified to be the bonafide work of the student in the PHYSICS INVESTIGATORY PROECT durin! the "ear #$%&'#$%( )

 

C!"#$%!& '(:))))))))))) )).

M$**. S+,$ B/!"!!

 

CONTENT 

AC*NO+,E-GE.ENT



CERTI/ICATE



THEORY



AI.



APPARAT0S



PROCE-0RE



O1SERVATION



RES0,T



1I1,IOGRAPHY

 

THEORY

+hen 2i!ht 3asses fro4 one 4ediu4 into an o3tica22" different 4ediu4 at an an!2e other than nor4a2 to the surface5 it is 6bent6 or under!oes a chan!e in direction5 4edia) This bendin!5 or chan!e in the direction of the ra" occurs on2" at the interface between the two 4ateria2s) The interaction of the 2i!ht with the trans3arent 4ateria2 chan!es the s3eed of 2i!ht as it 3asses throu!h the 4ateria2) The re2ationshi3 between the s3eed of 2i!ht in a 7acuu4 c and the s3eed of 2i!ht in the 4ateria2 7 is known as the inde8 of refraction n)The inde8 of refraction is defined in the fo22owin! e9uation: n ; c<7

=%>

+here c is the s3eed of the 2i!ht in 7acuu4 and 7 is the s3eed of the 2i!ht in 4ediu4) E9uation =%> can be used to find a re2ationshi3 between the an!2e of the incident wa7e5 sti22 4easured with res3ect to the nor4a25 and the an!2e of the 2i!ht ra" as it 4o7es throu!h this second 4ateria25 known as the an!2e of refraction) This new re2ationshi3 is known as Sne22?s ,aw5 stated 4athe4atica22" in the fo22owin! e9uation: n % sin=i> ;   n # sin=r> 

=#>

is the an!2e of incident5 =r> is the an!2e of refraction5 n % and n # are the indices of refraction of the first and the second 4ediu45 res3ecti7e2") If the incident 4ediu4 is air n % ; %5 then sin =i>   n # sin =r>  n # ; sin =i>< sin =r>  =

=@> =&>

AIM:Verification of Laws of Refraction of Light and Determination of Refractive Index of the Glass.

APPARATS :• • • • • •

A rectangular slab of glass, a laser pointer a few sheets of paper a sharp pencil a ruler A rotector

P"+!&,"! 

lace a flat sheet of paper on a flat surface.



lace or mount the laser pointer such that its ra! is not onl! hori"ontal to the sheet of paper, but also travels ver! close to its surface and leaves a strea# $line% of red light on the paper. &ome ad'ustment and practice is crucial.



(hen an uninterrupted strea# of light is present, place the rectangular or s)uare slab of glass on the flat paper such that the laser ra! is incident on a clear side it $as shown in the figure% and exits from the opposite side. (ith a sharp pencil, draw four straight lines around the slab in order to register the location of the slab on the paper. *he ra! incident  on side AA of the slab ma#ing angle i + with NN does refract and enters the slab through angle r +. &ee ig. In glass, it travels to the opposite side BB and becomes incident  on the other side through angle i - and finall! refracts bac# into air through angle r -. ar# two points on the incoming ra! and two dots on the outgoing ra! $with the sharpened pencil% in order to register their locations. a#e sure to mar# points 1 and 2 $points of incidence%



as well.



Lift the slab and turn the laser off. /n the paper, connect the mar#ed points in order to reproduce the laser ra! trace.



Draw two 00 $0ormal% lines as seen in the figure at points mar#ed 1 and 2. easure angles i+, r+, i-, and r- b! a protractor.



1se i+ and r+ and the &nell2s formula to find n, the refraction index of the glass slab. 1se i- and r- to find n again. ind the average of the two values !ou find for n. 1se this average as !our measured value for n.



Determine the index of refraction through !our observation