RCDD 12TH EDITION CHAPTER 1 WITH VERIFIED SOLUTIONS ALREADY GRADED A+

Electrical shock can cause = Death AC is voltage or current waveform = Is called a sine wave A sine wave cycle = Is one variation of the sine wave form zero to maximum (positive) back to zero in one second is called Frequency The number of times this cycle occurs in one second = Is called frequency Frequency is expressed in = Hertz (Hz) The amplitude (range) of the sine wave is expressed as either = Voltage or current Common mathematical method of measuring the amplitude of a sine wave = Is by its root mean square (rms) value The RMS value is = 0.7071 times the zero-to-peak value of the sine wave Phase difference is the relationship in time between = Two waveforms of the sam frequancy To measure phase difference = The time to complete one cycle is divided into 360 electrical degrees If two wave forms match each other in electrical degrees = They are said to be in phase The electrical system between the serving utility and the customers site is known as the = Distribution system Three characteristics of the various loads that affect the amount of power (watt) required for these loads = - Resistance - Inductance - Capacitance ohm's law states that V=IR where = - I = Current in amperes - V = Voltage in volts - R = Resistance in ohm's ohm's law can also be expressed as = R = V/I and I = V/R The formula for ohm's law always applies to = Direct current (dc) But the formula for ohm's law only applies to (ac) circuits = That are purely resistive, incandescent lamps and resistive heating elements Inductive reactance = Magnetic field Capacitive reactance (Xc) = Electric field In (ac) circuit that are purely resistive = The current and voltage sine waves are in phase Current lag voltage = Inductive wave In a circuit with inductive reactance there is a lag between the time the voltage waveform passes through zero = And the time the current waveform passes through zero Current leads voltage = Capacitive load The ratio of real power to apparent power is = A percentage and is called the power factor (PF) For a three phase circuit the phase voltage must be multiplied by = square root-3 (V3) when calculating power factor Watt = Indicate the amount of power that is consumed by a circuit at any given time Utility companies charge for power in Kilowatt HRS (kWh) 18,000 kWh x 24hr x 30 days 13332.0 x 7.5 = 99 (Btu) = British thermal units One watt is = 3.413 Btu/hr Watt x 3.413 = Heat dissipated in Btu Btu / 2watt = 6.836 Btu/12,000 = Tons of air conditioning required to maintain ambient temperature Horsepower (HP) = A unit of mechanical power In the AWG system = - Smaller number denotes larger wires - Larger number denotes smaller wires AWG system are based upon = Fixed diameters (36AWG =5mil) and the largest (4/0 = 460mil) Stranded conductors generally have a slightly larger outside diameter than the corresponding solid conductor diameter due to = The additional cross-sectional area between the stands Conductor sizes are specified in terms of the total cross-sectional area of the copper measured in circular Mils = Above 4/0 The AMP capacity of a conductor is related to = The conductor size, temperature, and means of insulation Transients/surge = Short duration (usually subcycle) rapid increase in voltage or current that can often be up to thousands of volts in amplitude Swell = Increase in nominal voltage or current lasting from 0.5 cycles to one minute Sag = A decrease in nominal voltage or current lasting 0.5 cycles up to one minute Interruption = A total absence of voltage on one or more phase conductors for a period of time Harmonics = Solid state Electronic ballasts = Generally causes harmonics Noise is = Unwanted electrical signals that are induced onto, or superimposed upon, the power line It is not recommended that voice and data equipment utilize = IG systems Isolated ground (IG) Orange or beige receptacle marked with an orange triangle upon its face