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Line Resistance, Inductance, and Capacitance Calculations — MCQs – EE

1. The resistance of a transmission line conductor depends on:

(A) Conductor material and length only


(B) Conductor material, length, and cross-sectional area


(C) Voltage only


(D) Tower height



2. The resistance of a conductor increases with:

(A) Decrease in temperature


(B) Increase in temperature


(C) Increase in conductor diameter


(D) Shorter conductor length



3. What is the unit of resistance per unit length?

(A) Ohm


(B) Ohm/km


(C) Ohm/volt


(D) Ohm/m²



4. Skin effect in AC transmission lines causes:

(A) Reduction of effective resistance at high frequency


(B) Increase of effective resistance at high frequency


(C) No change in resistance


(D) Only affects capacitance



5. The inductance of a transmission line depends mainly on:

(A) Conductor spacing and geometry


(B) Conductor material only


(C) Tower height only


(D) Line voltage only



6. For a single-phase line with two conductors, the inductance per unit length is given by:

(A) L = 2 × 10⁻⁷ ln(D/r) H/m


(B) L = 10⁻⁶ × D H/m


(C) L = 2 × 10⁻⁷ D² H/m


(D) L = 10⁻⁷ / D H/m



7. In three-phase lines, the concept of Geometric Mean Distance (GMD) is used to:

(A) Calculate resistance


(B) Calculate inductance


(C) Calculate capacitance only


(D) Calculate sag



8. The effect of conductor bundling on line inductance is:

(A) Increases inductance


(B) Reduces inductance


(C) No effect


(D) Only affects capacitance



9. The capacitance of a transmission line depends on:

(A) Conductor spacing and radius


(B) Conductor material only


(C) Tower height only


(D) Line current only



10. The capacitance per phase of a single-phase line with two conductors is:

(A) C = 2πε₀ / ln(D/r) F/m


(B) C = 2πε₀ ln(D/r) F/m


(C) C = 2π / ln(D/r) F/m


(D) C = 1 / 2πε₀ ln(D/r) F/m



11. Line resistance is considered:

(A) Series parameter


(B) Shunt parameter


(C) Both series and shunt


(D) Neither



12. Line inductance is considered:

(A) Series parameter


(B) Shunt parameter


(C) Both


(D) Neither



13. Line capacitance is considered:

(A) Series parameter


(B) Shunt parameter


(C) Series and shunt


(D) None



14. In three-phase lines, the Geometric Mean Radius (GMR) is used to:

(A) Calculate resistance


(B) Calculate inductance


(C) Calculate capacitance


(D) Calculate line sag



15. The unit of inductance per unit length is:

(A) Ohm/km


(B) Henry/km


(C) Farad/km


(D) Volt/km



16. The unit of capacitance per unit length is:

(A) Ohm/km


(B) Henry/km


(C) Farad/km


(D) Volt/km



17. The self-inductance of a conductor depends on:

(A) Its radius and spacing from other conductors


(B) Conductor length only


(C) Line voltage


(D) Tower height



18. Mutual inductance between conductors depends on:

(A) Distance between conductors


(B) Conductor radius only


(C) Tower height only


(D) Voltage



19. In a three-phase line, the inductance per phase can be calculated using:

(A) L = 2 × 10⁻⁷ ln(GMD/GMR) H/m


(B) L = 10⁻⁶ × ln(GMD/GMR) H/m


(C) L = 10⁻⁷ × ln(D/r) H/m


(D) L = 2 × 10⁻⁶ ln(D/r) H/m



20. The capacitance per phase in a three-phase line is calculated using:

(A) C = 2πε₀ / ln(GMD/GMR) F/m


(B) C = 2π / ln(D/r) F/m


(C) C = 2πε₀ ln(D/r) F/m


(D) C = ε₀ / ln(D/r) F/m



21. Stranded conductors are used to:

(A) Reduce skin effect


(B) Reduce line resistance


(C) Reduce corona loss


(D) Increase sag



22. Line resistance is negligible in:

(A) Short lines only


(B) Medium and long lines


(C) Underground cables


(D) DC transmission



23. Transposition of transmission lines is done to:

(A) Reduce resistance


(B) Balance inductance and capacitance among phases


(C) Reduce sag


(D) Reduce corona loss



24. The inductive reactance per unit length of a transmission line is given by:

(A) X_L = 2πfL Ω/km


(B) X_L = L/f Ω/km


(C) X_L = f/L Ω/km


(D) X_L = 2πL/f Ω/km



25. The capacitive reactance per unit length of a line is:

(A) X_C = 1 / (2πfC) Ω/km


(B) X_C = 2πfC Ω/km


(C) X_C = 1 / C Ω/km


(D) X_C = C Ω/km



26. The effective resistance of a conductor in AC is more than DC resistance due to:

(A) Skin effect


(B) Corona


(C) Capacitance


(D) Sag



27. Bundle conductors reduce:

(A) Resistance only


(B) Inductive reactance and corona loss


(C) Capacitance only


(D) Voltage drop only



28. The total series impedance of a line per unit length is:

(A) Z = R + jX_L


(B) Z = R + jX_C


(C) Z = 1 / (R + jX_L)


(D) Z = R × jX_L



29. The shunt admittance of a line per unit length is:

(A) Y = G + jB


(B) Y = R + jX


(C) Y = jX only


(D) Y = 1 / Z



30. To calculate resistance per km for a conductor at operating temperature, which factor must be considered?

(A) Temperature coefficient of resistance


(B) Line voltage


(C) Conductor spacing


(D) Tower height



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