Electrical resistivity and conductivity, series and parallel combinations of resistors, temperature dependence of resistance - Question Bank
1. The relation R = ρL/A defines resistance (R) in terms of resistivity (ρ), length (L), and cross-sectional area (A). If ρ is constant and L is doubled, what must happen to A to keep R constant?
2. What is the equivalent resistance of three identical resistors R connected in parallel?
3. What is the equivalent resistance of three identical resistors R connected in series?
4. A wire has resistance R. If it is melted and recast into a wire of half its length, the new resistance will be:
5. If the temperature of a conductor increases, its conductivity:
6. The resistivity of a material is independent of:
7. A circuit contains three resistors in series: 10 Ω, 20 Ω, and 30 Ω. If a 6V battery is connected across them, what is the current through the 20 Ω resistor?
8. A circuit contains three resistors in parallel: 10 Ω, 20 Ω, and 30 Ω. If a 6V battery is connected across them, what is the current through the 10 Ω resistor?
9. What is the primary reason for the increase in resistance of metals with temperature?
10. If a resistor of 100 Ω has a temperature coefficient of 0.004 /°C, what is its resistance at 100°C if its resistance at 0°C is 100 Ω?
11. A Nichrome wire is used in electric heaters because it has:
12. Which statement is true about the temperature dependence of resistance for semiconductors?
13. What does the temperature coefficient of resistance represent?
14. The relationship between conductivity (σ) and resistivity (ρ) is:
15. In a series circuit, if one of the resistors is removed (and the circuit is reconnected), the total resistance will:
16. In a parallel circuit, if one of the resistors is removed, the total resistance will:
17. Which of the following has the lowest resistivity at room temperature?
18. Which of the following has the highest resistivity at room temperature?
19. A wire of resistance R is cut into two equal halves. If these halves are connected in parallel, the equivalent resistance will be:
20. A wire of resistance R is stretched to double its length. The new resistance will be:
21. Resistivity of a material is an intrinsic property. Which of the following factors does NOT affect resistivity?
22. The SI unit of electrical conductivity is:
23. Consider two resistors, R1 = 10 Ω and R2 = 20 Ω. If they are connected in series, the equivalent resistance is:
24. Consider two resistors, R1 = 10 Ω and R2 = 20 Ω. If they are connected in parallel, the equivalent resistance is:
25. If three resistors of 2 Ω, 3 Ω, and 5 Ω are connected in parallel, what is the total resistance?
26. If three resistors of 2 Ω, 3 Ω, and 5 Ω are connected in series, what is the total resistance?
27. The resistance of a semiconductor generally:
28. Which material has a very low temperature coefficient of resistance, making it suitable for precision resistors?
29. Semiconductors like silicon and germanium typically have a temperature coefficient of resistance that is:
30. For most metals, the temperature coefficient of resistance (α) is:
31. The formula for the resistance at temperature T, R(T), for a metal is often given by R(T) = R0(1 + α(T - T0)), where α is the:
32. The temperature dependence of resistance for metals is generally described by:
33. What happens to the resistance of most metallic conductors when their temperature increases?
34. If two resistors R1 and R2 are connected in parallel, the equivalent resistance Req is:
35. If two resistors R1 and R2 are connected in series, the equivalent resistance Req is:
36. In a parallel combination of resistors, the voltage across each resistor is:
37. In a series combination of resistors, the current through each resistor is:
38. When resistors are connected in parallel, the total resistance is:
39. When resistors are connected in series, the total resistance is:
40. For a given material, resistance is independent of:
41. If the cross-sectional area of a wire is doubled, its resistance will:
42. If the length of a wire is doubled, its resistance will:
43. The resistance of a wire is inversely proportional to its:
44. The resistance of a wire is directly proportional to its:
45. Which of the following is a good electrical insulator?
46. Which of the following is a good electrical conductor?
47. A material with high electrical resistivity will have:
48. Electrical conductivity is the reciprocal of which property?
49. Which of the following units is used to measure electrical resistivity?
50. What is electrical resistivity?