NCATT 3
The capacitive reactance in a 90 Hz AC circuit with a capacitance of .3 F is?
A. 0.007795 ohms
B. 0.04 ohms
C. 0.001 ohms
D. 0.0118 ohms - answerA. 0.007795 ohms
If a circuit contains 80 ohms of capacitive reactance and 40 ohms of inductive
reactance, what is the net reactance?
A. 40 owns inductive reactance.
B. 120 ohms reactance
C. 40 owns capacitive reactance.
D. -40 ohms inductive reactance - answerB. 40 owns capacitive reactance.
If a series circuit contains 4 ohms of resistance and five ohms of reactance, what is the
impedance?
A. 7.2 ohms
B. 5.6 ohms
C. 1.8 ohms.
D. 25.8 ohms - answerB. 5.6 ohms
Which of these does not affect the value of capacitance in a capacitor?
A. Distance between the plates.
B. The dielectric constant.
C. Plate area.
D. Applied voltage. - answerA. Distance between the plates.
Of these for materials used as a dielectric, which is the best insulator?
A. Pure water.
B. Petroleum.
C. Glass.
D. Air. - answerC. Glass.
A capacitor with a voltage rating of 500 V cannot be used when the effective voltage in
the circuit is 450 V AC because of?
A. The average voltage will exceed the capacitors rating.
, B. The current flow under that voltage will short capacitor.
C. The peak voltage in the circuit will exceed the capacitor's rating.
D. The peak voltage is just under 500 V, but you must allow a fudge factor in case of a
power surge. - answerC. The peak voltage in the circuit will exceed the capacitors
rating.
Inductive reactance is measured in?
A. Henrys
B. Farads
C. Amps.
D. Ohms - answerD. Ohms
Which of these statements about electrostatic fields is false?
A. Electrostatic fields are polarized from positive to negative.
B. Electrostatic fields have the ability to pass through any known material.
C. Electrostatic fields have the ability to distort the orbits of tightly bound electrons.
D. Electrostatic field radiate from a charged particle in a closed loop. - answerD.
Electrostatic fields radiate from a charged particle in closed loops
The two metal plates in a simple capacitor are separated by a?
A. A radiator.
B. A conductor.
C. A dielectric.
D. An inductor. - answerC. Dielectric.
The maximum current in an inductor is 30 A. One L/R time constant after voltage is
applied, the current will be?
A. 6.32 A.
B. 11.04 A.
C. 18.96 A.
D. 9.65 A. - answerC. 18.96 A
In an iron-core inductor, power that is consumed in reversing the magnetic field of the
inductor core each time the direction of current changes is known as?
A. Hysteresis loss
B. Copper loss.
C. Eddy current.
D. AC loss - answerA. Hysteresis loss
Which of these does not affect coil inductance?
The capacitive reactance in a 90 Hz AC circuit with a capacitance of .3 F is?
A. 0.007795 ohms
B. 0.04 ohms
C. 0.001 ohms
D. 0.0118 ohms - answerA. 0.007795 ohms
If a circuit contains 80 ohms of capacitive reactance and 40 ohms of inductive
reactance, what is the net reactance?
A. 40 owns inductive reactance.
B. 120 ohms reactance
C. 40 owns capacitive reactance.
D. -40 ohms inductive reactance - answerB. 40 owns capacitive reactance.
If a series circuit contains 4 ohms of resistance and five ohms of reactance, what is the
impedance?
A. 7.2 ohms
B. 5.6 ohms
C. 1.8 ohms.
D. 25.8 ohms - answerB. 5.6 ohms
Which of these does not affect the value of capacitance in a capacitor?
A. Distance between the plates.
B. The dielectric constant.
C. Plate area.
D. Applied voltage. - answerA. Distance between the plates.
Of these for materials used as a dielectric, which is the best insulator?
A. Pure water.
B. Petroleum.
C. Glass.
D. Air. - answerC. Glass.
A capacitor with a voltage rating of 500 V cannot be used when the effective voltage in
the circuit is 450 V AC because of?
A. The average voltage will exceed the capacitors rating.
, B. The current flow under that voltage will short capacitor.
C. The peak voltage in the circuit will exceed the capacitor's rating.
D. The peak voltage is just under 500 V, but you must allow a fudge factor in case of a
power surge. - answerC. The peak voltage in the circuit will exceed the capacitors
rating.
Inductive reactance is measured in?
A. Henrys
B. Farads
C. Amps.
D. Ohms - answerD. Ohms
Which of these statements about electrostatic fields is false?
A. Electrostatic fields are polarized from positive to negative.
B. Electrostatic fields have the ability to pass through any known material.
C. Electrostatic fields have the ability to distort the orbits of tightly bound electrons.
D. Electrostatic field radiate from a charged particle in a closed loop. - answerD.
Electrostatic fields radiate from a charged particle in closed loops
The two metal plates in a simple capacitor are separated by a?
A. A radiator.
B. A conductor.
C. A dielectric.
D. An inductor. - answerC. Dielectric.
The maximum current in an inductor is 30 A. One L/R time constant after voltage is
applied, the current will be?
A. 6.32 A.
B. 11.04 A.
C. 18.96 A.
D. 9.65 A. - answerC. 18.96 A
In an iron-core inductor, power that is consumed in reversing the magnetic field of the
inductor core each time the direction of current changes is known as?
A. Hysteresis loss
B. Copper loss.
C. Eddy current.
D. AC loss - answerA. Hysteresis loss
Which of these does not affect coil inductance?
