O’zbekiston respublikasi oliy va o`rta maxsus ta`lim vazirligi

1-laboratoriya ishi. Ignalar yordamida yassi parallel shisha plastinkaning nur 
sindirish ko’rsatkichini aniqlash.
Ishining maqsadi:
tajriba orqali ba’zi moddalarning sindirish ko’rsatgchini 
aniqlash va xulosalar chiqarish. 
Kerakli asboblar: 1. Penoplast taglik. 2. Ignalar. 3. Qog’oz. 4. Qalam, chizg’ich, 
shisha plastinka. 
Nazariy qism 
Yorug’lik nuri ikki shafof muhitlar chegarasiga tushganda ikki qismga 
ajralib, ulardan biri o’zi kelgan muhitga qaytsa, ikkinchi qismi chegaradan sinib 
o’tib ikkinchi muhitda tarqaladi.Yorug’likning tarqalish yo’nalishini ikki muhit 
chegarasidan o’tishida o’zgarishi yorug’likning sinishi deyiladi. 1-rasmda qaytgan, 
singan nurlar normal va ikki muhit chegarasida ko’rsatilgan: AO- tushuvchi nur; 
NN
’
– normal, OB – qaytgan nur, OS – singan nur, MM-muhitlar chegarasi, α – 
tushish burchagi, α
’
– qaytish burchagi, β – sinish burchagi. 
1-rasm. 
Yorug’likning sinish qonunini keltirib chiqarish uchun Gyuygens prinsipini 
qo’llaymiz. Aytaylik ikki muhit chegarsiga AB yorug’lik dastasi tushsin (2-rasm). 
To’lqin fronti AS nurning AB chegaralariga tik MM chegara dastlab AA nur etib 
keladi. BB nur esa chegaraga
Δt=BS/υ
1

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12 
2-rasm
. 
vaqtdan so’ng etib keladi. υ
1
- birinchi muhitdagi yorug’lik tezligi. B nuqtada 
ikkilamchi to’lqin uyg’ona boshlaganda A nuqtada yuzaga kelgan to’lqinlar AD= 
υ
2
Δt radiusli yarim sferalar chizadilar. υ
2
- ikkinchi muhitdagi yorug’lik tezligi. 
Shakldan <α=ΔABS dan sinα=BS/AB= υ
1
Δt/AB (2) 
ΔABD dan sinβ=AD/AB= υ
2
Δt/AB
(3) 
(2) ifodadan AB ni topib (3) ifodaga qo’ysak,
(4) 
Muhitning absolyut sindirish ko’rsatgichidan 
dan foydalanib topiladi.
(5) 
Bu yerda 
m/s yorug’likning bo’shliqdagi tezligidir. 
Demak, tushish burchagi sinusining sinish burchagi sinusiga nisbati ikkinchi 
muhitning birinchi muhitga nisbatan nisbiy sindirish ko’rsatgichiga teng bo’lar 
ekan. 
Ishni bajarish tartibi 
1.
Yassi tekislikka penoplast taglik o’rnatiladi.
2.
Oq katakli qog’oz penoplast taglik ustiga qo’yiladi. 
3.
Shisha plastinka qog’ozning o’rtasiga joylashtiriladi. 
4.
Qog’ozga qalam bilan shisha plastinkaning sindiruvchi yoqlari bo’ylab 
chiziladi. 

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13 
5.
Plastinkaning bir yog’i yaqinidagi A va B nuqtalarga ignalar tik holda 
qadaladi. Plastinkaning ikkinchi yog’iga C va D ignalarni tik holda shunday 
qadaladiki, shisha orqali qaralganda to’rtala ignalarning asoslari bir to’g’ri 
chiziqda turgandek ko’rinadi. 
6.
Ignalar olib tashlanib ular o’rinlari bekgilab olinadi. 
Yorug’lik nuri AB yonalish bo’yicha shishaga tushadi. B nuqtada u 
singan C nuqtaga keladi. So’ngra shishaning ikkinchi tomonida CD 
yo’nalish bo’yicha tarqaladi.
7.
Suvning sindirish ko’rsatgichini hisoblash uchun transporter yordamida α va 
β burchaklar o’lchanadi. Ularning sinuslari qiymatlari (5) formulaga qo’yilib 
n hisoblanadi.
Shakldan foydalangan holda hisoblash quyidagicha bajariladi: 
;
AK, AB, NC kesmalarni chizg’ich bilan o’lchanadi va 
n
hisoblanadi (3-rasm): 
3-rasm. 

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14 
8.
Tajriba 3-4 marta takrorlanadi va natijalar jadvalga yoziladi. 
№ 
α 
β 
AK 
AB 
NC 
BC 
n 
∆n 
ε 
1 
2 
3 
4 
 
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