O'zgarmas tok qonunlari — Masalalar yechish — 10-sinf Fizika test savollari

1.O'tkazgichning 0 °C dagi qarshiligi 250 Ω, ma'lum bir temperaturada esa 2000 Ω ga teng bo'lsa, shu temperaturani toping (qarshilikning termik koeffitsiyenti 0,005 °C⁻¹).

• A)1400 °C
• B)1600 °C
• C)700 °C
• D)2800 °C

2.0 °C temperaturadagi alyuminiyning qarshiligini 4 marta orttirish uchun uni qanday temperaturagacha qizdirish kerak? (Alyuminiy uchun α = 0,004 °C⁻¹.)

• A)1000 °C
• B)750 °C
• C)375 °C
• D)1500 °C

3.Volfram o'tkazgichning 0 °C dagi qarshiligi 100 Ω, ma'lum temperaturada uning qarshiligi 150 Ω bo'lib qoldi. Agar bu temperatura 200 °C bo'lsa, qarshilikning termik koeffitsiyenti (α) qanchaga teng?

• A)0,0075 °C⁻¹
• B)0,00125 °C⁻¹
• C)0,0025 °C⁻¹
• D)0,005 °C⁻¹

4.O'tkazgichning 0 °C dagi qarshiligi 180 Ω, ma'lum bir temperaturada esa 900 Ω ga teng bo'lsa, shu temperaturani toping (qarshilikning termik koeffitsiyenti 0,004 °C⁻¹).

• A)1250 °C
• B)500 °C
• C)2000 °C
• D)1000 °C

5.0 °C temperaturadagi metall o'tkazgichning qarshiligini 2 marta orttirish uchun uni qanday temperaturagacha qizdirish kerak? (Qarshilikning termik koeffitsiyenti 0,005 °C⁻¹.)

• A)200 °C
• B)400 °C
• C)100 °C
• D)600 °C

6.Cho'g'lanma lampochka volfram tolasining 20 °C dagi qarshiligi R1 = 30 Ω. Lampochka U = 100 V kuchlanishli manbaga ulanganda I = 0,25 A tok o'tsa, tolaning shu paytdagi temperaturasini toping (volfram uchun α = 4,6·10⁻³ °C⁻¹).

• A)2681 °C
• B)2948 °C
• C)1474 °C
• D)5896 °C

7.Elektr lampochkadagi volfram tolasining 20 °C dagi qarshiligi 25,5 Ω. Lampochka 110 V kuchlanishli tarmoqqa ulanganda toladan 0,28 A tok oqib o'tsa, tolaning temperaturasini aniqlang (α = 4,6·10⁻³ °C⁻¹).

• A)3132 °C
• B)1720 °C
• C)3440 °C
• D)6880 °C

8.Mis simli g'altak chulg'amining qarshiligi 10 °C da 8 Ω ga teng. Tokka ulangandan keyin chulg'amning qarshiligi 9,6 Ω ga teng bo'ldi. Chulg'am qancha temperaturagacha qiziydi? (Mis uchun α = 4,15·10⁻³ °C⁻¹.)

• A)48 °C
• B)30 °C
• C)120 °C
• D)60 °C

9.Temir simdan qilingan reostat, milliampermetr va tok manbai ketma-ket ulangan. Temperatura 0 °C bo'lganda reostat qarshiligi R = 150 Ω, milliampermetrning qarshiligi r = 15 Ω, ko'rsatishi $I_0$ = 25 mA. Agar reostat 40 °C ga qizdirilsa, milliampermetr qanday qiymatni ko'rsatadi? (Temir uchun α = 6·10⁻³ °C⁻¹, manbaning ichki qarshiligini hisobga olmang.)

• A)20,5 mA
• B)18,7 mA
• C)22,2 mA
• D)25,0 mA

10.Temperatura t1 = 0 °C dan t2 = 40 °C gacha o'zgarganda, chulg'ami mis simdan qilingan elektromagnit iste'mol qiladigan quvvat necha foizga o'zgaradi? (Mis uchun α = 4,3·10⁻³ °C⁻¹.)

• A)14,68% ga ortadi
• B)14,68% ga kamayadi
• C)17,2% ga kamayadi
• D)7,3% ga kamayadi