E405

ABSTRACT

The Experiment 405 is all about diffraction which is the slight bending of light as it  passes around the edge of an object. By using Snells !aw formula" the group was able to get the angle of refraction. Based on the results obtained by the group" the light wa#es reaching a gi#en point on the screen each arri#e from a different part of the slit" so their amplitudes must  be added" and a pattern results. The pattern formed by the interference and diffraction of  coherent light is distinctly different for a single and double slit. The single slit intensity en#elope is shown by the dashed line and that of the double slit for a particular wa#elength and slit width is shown by the solid line. $n conclusion" the absolute minima or maxima is directly proportional to their patterns positions.

CONCLUSION

$n this experiment" we were able to explore the phenomenon of diffraction of light" and to compare a single slit diffraction and two slit interference. The diffraction is described as the apparent bending of wa#es around small obstacles and the spreading out of wa#es past small openings" while the interference is two wa#es superimpose to form a resultant wa#e of  greater or lower amplitude. %onstructi#e interference occurs when the phase difference  between the wa#es is a multiple of &'" whereas destructi#e interference occurs when the difference is '" ('" 5'" etc. the distance of e#ery minima and maxima are e)ual to each other. The measurement of the minima and maxima increases as the slit decreases. The measurement of the minima and maxima decreases as the distance of the screen to the slit decreases. *e must also consider se#eral factor in performing the experiment" we must +now what +ind of color the laser produces in able to +now the wa#elength of that specific color   because e#ery color ha#e different wa#elength. $n real life application" for diffraction" if a radio is turned on in one room" the sound from the radio can be heard in an adjacent room e#en from around a doorway. ,n example of interference also radio wa#es which interfere with each other when they bounce off buildings in cities" distorting radio signals. Soundwa#e interference must be ta+en into account when constructing concert halls" so that destructi#e interference does not result in areas in the hall where the sounds produced on stage cannot be heard.

SAMPLE COMPUTATION

Table  /i#en

a =0.16 m m ; x = 90 cm

 y m=

m1=0.40 cm

λ=

( 0.40 )( 0.16 ) 1 ( 90 )

 λ =711.11 nm

m2=0.75 cm

λ=

( 0.75 )( 0.16 ) 2 (90 )

 λ =666.67 nm

m3=0.40 cm

λ=

( 1.10 )( 0.16 ) 3 (90 )

 λ =651.85 nm

m−1=1.10 cm

λ=

( 0.40 )( 0.16 ) 1 ( 90 )

 λ =711.11 nm

m−2= 0.75 cm

λ=

(0.75 )( 0.16 ) 2 ( 90 )

 λ =666.67 nm

m−3=1.10 cm

λ=

(1.10 )( 0.16 ) 3 ( 90 )

 λ =651.85 nm

mxλ a

Ave λ=

711.11

+ 666.67 + 651.85 3

 λaverage =676.54 nm

%alculated

 λ =

 y m a mx

%error =

676.54

−670

670

× 100

 

%error = 0.98

Table & /i#en

a =0.08 mm;d = 0.50 mm;x =90 cm

 y m=

m1=1.20 cm

λ=

( 1.20 )( 0.50 ) 1 (90 )

 λ =666.67 nm

m2=2.30 cm

λ=

( 2.30 )( 0.50 ) 2 ( 90 )

 λ =638.89 nm

m3=3.70 cm

λ=

( 3.70 )( 0.50 ) 3 ( 90 )

 λ =685.19 nm

m−1=1.20 cm

λ=

(1.20 )( 0.50 ) 1 ( 90 )

m−2=2.30 cm

λ=

( 2.30 )( 0.50 ) 2 ( 90 )

 λ =638.89 nm

m−3= 3.70 cm

λ=

( 3.70 )( 0.50 ) 3 ( 90 )

 λ =685.19 nm

mxλ d

Ave λ=

666.67

λ =666.67 nm

+ 638.89 + 685.19 3

 λaverage =663.58 nm

%alculated

 λ =

 y m d mx

%error =

670

−663.58 670

× 100

 

%error = 0.96