Fizika8 Uzb i-bob 1-26. pmd

19-§. REOSTAT YORDAMIDA TOK KUCHINI ROSTLASH
(laboratoriya ishi)
Kerakli jihozlar: tok manbayi, reostat, ampermetr, voltmetr, kalit va ulov-
chi simlar.
70-rasm
71-rasm
72-rasm
18-§. Rezistorlar. Reostatlar. Potensiometrlar

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52
II bob. Elektr toki
Ishni bajarish tartibi
1. Tok manbayi, reostat, amper-
metr, voltmetr va kalitdan iborat
bo‘lgan zanjirni yig‘ing (73-rasm).
2. Elektr zanjir sxemasini chi-
zing.
3. Kalitni ulang va voltmetr ko‘r-
satgan  U kuchlanishni 4-jadvalga
yozing.
4. Reostat surgichini sterjen bo‘y-
lab bir me’yorda o‘ngdan chapga va
chapdan o‘ngga suring. Bunda kuch-
lanish o‘zgarmaganligi, lekin tok ku-
chi bir me’yorda o‘zgarishini kuza-
ting.
5. Reostat surgichini sterjen uzun-
ligining 1/4 qismiga suring. Amper-
metrning  I
1
 ko‘rsatkichini yozib oling. Om qonuni formulasidan R
1
 
=
  U/I
1
qarshilikni toping.
6. Reostat surgichini sterjenning o‘rtasiga suring. Ampermetrning I
2
ko‘rsatkichini yozib oling. Om qonuni formulasidan R
2
 = U/I
2
 qarshilikni
toping.
7. Reostat surgichini sterjenning taxminan 3/4 qismiga suring. Amper-
metrning  I
3
 ko‘rsatkichini yozib oling. Om qonuni formulasidan R
3 
=U/I
3
qarshilikni toping.
8. Reostat surgichini o‘ngga sterjenning oxirigacha suring. Ampermetr-
ning  I
4
 ko‘rsatkichini yozib oling. Om qonuni formulasidan R
4 
=U/I
4
qarshilikni toping.
9. Natijalarni tahlil qiling va xulosa chiqaring.
4-jadval
¹                  U,  V                                  I, A
      R,  Ω
1
2
3
4
1. Ampermetr reostatga qanday ulanadi?
2. Reostatdagi kuchlanish qanday o‘lchanadi?
3. Om qonuni formulasi qanday ifodalanadi?
4. Reostat surgichi surilganda zanjirdagi tok kuchi nima sababdan o‘zgaradi?
73-rasm

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