Alternating Current Theory

Why must RMS values be used instead of peak values in most AC measurements?

RMS corresponds to actual power and heating effect in circuits

A household AC supply of 110 V represents:

The effective RMS value

Which two effects occur only in AC circuits and not in DC circuits?

Inductive reactance and capacitive reactance

What advantage do AC motors offer over DC motors in aircraft?

AC motors eliminate commutation issues at altitude

At which conductor position is the induced voltage maximum positive?

Perpendicular to the flux lines in upward motion

Wavelength is measured as:

The distance traveled by a waveform in one cycle

Why is AC more suitable than DC for long-distance transmission in aircraft and commercial power systems?

AC allows voltage to be stepped up or down using transformers

Which combination represents the total opposition to AC current flow?

Resistance, inductive reactance, and capacitive reactance

What risk exists if two aircraft AC busses are not synchronized in phase?

Damage may occur to aircraft systems or avionics

What is the standard unit of frequency in AC systems?

Hertz (Hz)

Which factor does not determine the value of induced emf in a conductor?

Type of insulating material around the conductor

How does inductive reactance affect AC circuits?

It opposes changes in current due to magnetic fields

The effective value of AC is best described as:

The same as the average DC voltage producing identical heating effect

According to Faraday's discovery, what condition must exist for current to be induced in a conductor?

Relative motion between the conductor and the magnetic field

One complete AC cycle consists of:

One positive and one negative alternation

If voltage and current rise and fall together, the two waveforms are:

In phase

What is the mathematical relationship between RMS and peak value of AC?

Vrms = 0.707 x Vp

The period of a sine wave is defined as:

The time required for one complete cycle

In a 2-pole generator running at 3600 rpm, the AC frequency is:

60 Hz

In comparing AC and DC waveforms, what characteristic makes AC unique?

Alternating direction and magnitude over time

In an AC generator, why are slip rings used instead of commutators?

They allow continuous transfer of alternating current

Lenz's Law states that an induced current will:

Oppose the motion that produced it

What does the sine wave at Position 5 in generator rotation represent?

The polarity and magnitude of induced voltage over time

When one waveform reaches maximum before another, it is said to:

Lead the other

The instantaneous value of AC voltage is defined as:

The value at any given moment in the cycle