NETA AC/DC Theory and Circuits 5

Question 1

In a three-phase delta-connected system with a line voltage of 208 V, what is the phase voltage?

Accepted Answer

208 V

Answer

In a delta connection, the phase voltage equals the line voltage, so Vphase = 208 V.

Question 2

What happens to the total capacitance when capacitors are connected in series?

Accepted Answer

Total capacitance is less than the smallest individual capacitance

Answer

Capacitors in series combine like resistors in parallel; the total is always less than the smallest individual value.

Question 3

Skin effect in AC conductors causes current to:

Accepted Answer

Concentrate near the outer surface of the conductor

Answer

At higher AC frequencies, skin effect causes current density to concentrate near the conductor surface, increasing effective resistance.

Question 4

A 60 Hz AC circuit has an inductance of 0.1 H. What is the inductive reactance?

Accepted Answer

37.7 Ω

Answer

XL = 2πfL = 2π × 60 × 0.1 ≈ 37.7 Ω.

Question 5

Which law states that the algebraic sum of all currents entering and leaving a node in a circuit equals zero?

Accepted Answer

Kirchhoff's Current Law

Answer

Kirchhoff's Current Law (KCL) states that the sum of currents entering a node equals the sum leaving it.

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