Electrical Theory and Principles Flashcards

A conductor carrying current is placed in a magnetic field. The resulting force on the conductor is described by:

Answer: The Left-Hand Rule (motor action)

The Left-Hand Rule (Fleming's) determines the direction of force on a current-carrying conductor in a magnetic field (motor action).

What is the effect of increasing wire gauge number (AWG) on conductor resistance?

Answer: Resistance increases

Higher AWG numbers indicate smaller diameter conductors, which have higher resistance per unit length.

Which of the following is true about apparent power in an AC circuit?

Answer: It is the product of RMS voltage and RMS current

Apparent power (S) in volt-amperes (VA) equals the product of RMS voltage and RMS current: S = Vrms × Irms.

Lenz's Law is best described as:

Answer: The induced EMF drives a current that opposes the change causing it

Lenz's Law states that the induced current flows in a direction to oppose the change in magnetic flux that caused it.

What is the resonant frequency of a series LC circuit with L = 50 mH and C = 20 µF?

Answer: 159 Hz

fr = 1/(2π√LC) = 1/(2π√(0.05 × 20×10⁻⁶)) ≈ 159 Hz.

In a delta (Δ) connected 3-phase system, the relationship between line current and phase current is:

Answer: IL = Iφ × √3

In a delta connection, the line current equals the phase current multiplied by √3.

Which property of a material determines how easily it can be magnetized?

Answer: Permeability

Permeability (µ) measures how easily a material supports the formation of a magnetic field within it.