LEVEL 2 MODULE 1 VOCAB
DEFINITIONS (ABC APPRENTICE YEAR
2) QUESTIONS AND ANSWERS WITH
SOLUTIONS 2024
Frequency - ANSWER The number of cycles an alternating electric current, sound wave, or vibrating
object undergoes per second.
Hertz (Hz) - ANSWER A unit of frequency; one hertz equals one cycle per second.
Peak Voltage - ANSWER The peak value of a sinusoidally varying (cyclical) voltage or current is equal to
the root-mean-square (rms) value multiplied by the square root of two (1.414). AC voltages are usually
expressed as rms values; that is, 120 volts, 208 volts, 240 volts, 277 volts, 480 volts etc. are all rms
values. The peak voltage, however differs. For example, the peak value of 120 volts (rms) is actually 120 x
1.414 = 169.71 volts.
Radian - ANSWER An angle at the center of a circle, subtending (opposite to) an arc of the circle that is
equal in length to the radius.
Root-mean-square (rms) - ANSWER The square root of the average of the square of the function taken
throughout the period. The rms value of a sinusoidally varying voltage or current is the effective value of
the voltage or current
Capacitance - ANSWER The storage of electricity in a capacitor; capacitance produces an opposition to
voltage change. The unit of measurement for capacitance is the Farad (F) or microfarad (uF).
Impedance - ANSWER The opposition to current flow in an AC circuit; impedance includes resistance (R),
capacitive ractance (Xc), and inductive reactance (Xl). Impedance is measured in ohms (omega symbol)
Inductance - ANSWER The creation of a voltage due to a time-varying current; also, the opposition to
current change, causing current changes to lag behind voltage changes. The unit of measure for
inductance is the henry (H).
DEFINITIONS (ABC APPRENTICE YEAR
2) QUESTIONS AND ANSWERS WITH
SOLUTIONS 2024
Frequency - ANSWER The number of cycles an alternating electric current, sound wave, or vibrating
object undergoes per second.
Hertz (Hz) - ANSWER A unit of frequency; one hertz equals one cycle per second.
Peak Voltage - ANSWER The peak value of a sinusoidally varying (cyclical) voltage or current is equal to
the root-mean-square (rms) value multiplied by the square root of two (1.414). AC voltages are usually
expressed as rms values; that is, 120 volts, 208 volts, 240 volts, 277 volts, 480 volts etc. are all rms
values. The peak voltage, however differs. For example, the peak value of 120 volts (rms) is actually 120 x
1.414 = 169.71 volts.
Radian - ANSWER An angle at the center of a circle, subtending (opposite to) an arc of the circle that is
equal in length to the radius.
Root-mean-square (rms) - ANSWER The square root of the average of the square of the function taken
throughout the period. The rms value of a sinusoidally varying voltage or current is the effective value of
the voltage or current
Capacitance - ANSWER The storage of electricity in a capacitor; capacitance produces an opposition to
voltage change. The unit of measurement for capacitance is the Farad (F) or microfarad (uF).
Impedance - ANSWER The opposition to current flow in an AC circuit; impedance includes resistance (R),
capacitive ractance (Xc), and inductive reactance (Xl). Impedance is measured in ohms (omega symbol)
Inductance - ANSWER The creation of a voltage due to a time-varying current; also, the opposition to
current change, causing current changes to lag behind voltage changes. The unit of measure for
inductance is the henry (H).
