M3

Electromotive force makes (3.3). atoms in flow. protons in flow. electron in flow.

Electrical energy is measured in (8.4). In Ws or more recognizable from electric bill in kWh. In WA or more recognizable from electric bill in kWA. in Horse power or more recognizable from electric bill in dolars.

Ferrous materials have (10.5). Small permeability. Huge permeability. No permeability.

What is the benefit of AC against DC power? (13.2). it can be transmitted long distance more readily and economically. it can be transmitted along cheaper wires. it Is easier to be produced.

RMS (Root Mean Square) value means: (13.8). Peak value multiplied by 1,41. Peak value multiplied with square root of three. Peak value divided by 1,41.

Does capacitive reactance becomes larger or smaller as frequency decrease ? (14.6). Does not change. Larger. Smaller.

Does inductive reactance becomes larger or smaller as frequency increase ?(14.6). Smaller. Does not change. Larger.

A Transformer has 500 secondary turns and 4500 primary turns. Its ratio is: (15.2). 9 against 1. 9 against 2. 1 against 9.

Single phase alternator has (17.3). rotor windings connected in series. stator windings connected In series. stator and rotor windings connected in series.

Types of AC motors are: (18.2). Step and induction motors. Synchronous and step motors. Synchronous and induction motors.

Constant speed drive is constructed to deliver output constant (17.12). RPMs. frequency. torque.

What current supplies the field of an AC generator? (17.2). AC or DC. AC. DC.

Inductive reactance is 10 Ohms, capacitive reactance is 7 Ohms and resistance is 4 Ohms. How much is impedance? (14.4). 5 Ohms. 21 Ohms. 17 Ohms.

The empty space between capacitor plates is filled by nonconductor called: (9.2). dielectric. monoelectric. salt water.

What kind of dielectrics are used?. Paper, oil, electrolitic, ceramic. Paper, oil. sweet water, ceramic. Paper, oil. salt water, ceramic.

What happens with magnetic poles when a magnet is broken on two parts? (10.4). Each part has new N and S pole. Each part has either N or S pole but never both. These two parts are not magnetized any more.

What is the key for electricity production in generators? (12.2). Electromagnetic induction. Capacitance. Electromagnetic resistance.

If the frequency is 8 Hz (13.6). then the period of one cycle of AC power is 0,125 s. then the period of one cycle of AC power is 0,225 s. then the period of one cycle of AC power is 0,100 s.

The frequency of a wave with a time period of 1 ms is (13.6). 1000 Hz. 10.000 Hz. 100 Hz.

The AC sine curve can be presented in a circle. The value of the sine in quadrant two of Cartesian system: (13.7). increases in negative direction from 0 to -1. decreases from 1 to 0. increases from 0 to 1.

The capacitive reactance in AC circuit: (14.2). acts opposite to inductive reactance. is proportional to the capacitance and frequency. is inversely proportional to the capacitance and proportional to the frequency.

General power formula is: (8.3). Power = Current / Voltage. Power = Current x Voltage. Power = Voltage / Current.

How much power do we get from circuit with electrical current I=4A and voltage E=20V? (8.3). 80W. 0.2W. 5W.

Permanent magnets may loose their magnetism by (10.8). heating them on higher temperatures. cooling them below 0‘C. stonng them on room temperature.

In an autotransformer (15.4). Primary coil and secondary coil share some of the windings. have the same amount of primary and secondary windings. have separated primary and secondary windings.

Electronic circuit designed to let pass AC frequency band limitted by upper and lower cut-off frequency is called? (16.4). Band pass filter. High pass filter. Low pass filter.

Simple electronic device having a single signal transmission frequency band extending from zero frequency ( DC) up to some cutt-off frequency which is not infinite is called (16.4). Low pass filter. High pass filter. Band pass filter.

A transformer has 200 W and 400V at primary winding. What is the current ? (15.5). 1/2 Amps. 0.05 Amps. 2 Amps.

Resistance and reactance always (14.2). act at right angle to each other. act against each other. act at 60° angle to each other.

When operating two AC generators paralleled (on the same bus), the phase of both generators (17.12). must be synchronous (which means exactly in phase). must be out of phase for 120°. must be in opposition.

What will be RPMs of an motor with f=60Hz, P=4?(18.3). 900 RPM. 600 RPM. 1800 RPM.

Capacitors are: (9.2). kind of resistors. storage for electricity. storage for magnetism.

33. A transformer has 200V, 500 turns on the primary and 50 turns on the secondary. What would be the voltage in the secondary ? (15.3). 2000V. 20V. 50V.

Current transformers are (15.5). used as circuit protection and control devices. not available. used as voltage multiplier for high voltages.

Electronic circuit which has a single transmission band from one cut-off frequency up to infinite frequeny is called (16.4). High pass filter. Low pass filter. Band pass filter.

In two phase alternator (17.3). both phases are 90º out of phase,. both phases are 45º out of phase. both phases are 180º out of phase.

Three phase synchronous motor has ? (18.2). three stator windings and one rotor winding. three rotor windings and one stator windings. three rotor windings and three stator windings.

One cycle at AC power generation is finished when (13.6). when one turn of the rotor is done. when half turn of the rotor is done. when two turns of the rotor is done.

IONS are atoms with: (1.3). Lack or "overnumber" of electrons. Lack of neutrons. Too many neutrons.

Positive ions are: (1.4). Atoms with higher number of protons. Atoms with higher number of neutrons. Atoms with higher number of electrons.

Equivalent resistance of parallel connected resistors is (6.8). 1/Rn = 1/R1 + 1/R2 + 1/R3 ... we use 2nd Kirkoffs law for calculation. Rn= R1 + R2 + R3.

A resistor of 5 Ohm is in series with a resistor of 8 Ohm. What is the approximate equivalent resistance? (6.2). 13 Ohm. 10 Ohm. 40 Ohm.

A thermistor has a (7.10). Negative temperature coefficient in that as temperature rises, resistance decreases. Positive temperature coefficient. Positive temperature coefficient.

The resistance of a conductor is inverserly propotional to the cross section area! (7.4). True. False. False because the material of conductor only matters.

Power is defined: (8.2). As the rate of consumed energy in time. As the rate of consumed current in time. As the rate of consumed resistance in time.

Frequency is: (13.6). Number of cycles in a period. Number of max + min values in a period. Time required for a cycle.

If two waves are not in phase (13.S). the current can lag or lead the voltage. the current is in phase to the voltage. the current can only lag the voltage.

Resistance and reactance (14.2). are two forces acting at 90º angle to each other. are two forces acting at 180º angle to each other. are two forces acting at 0º angle to each other.

Impedance is 10 ohms, resistance is 6 ohms. How much is reactance? (14.3). 11,8 ohms. 60 ohms. 8 ohms.

Transformers (15.2). Changes electrical energy of a given voltage level to an energy at different voltage level. Changes electrical energy of a given voltage level to an energy at higher voltage level only. Changes electrical energy of a given voltage level to an energy at lower voltage level only.

Constant speed drive is an device installed between (17.13). engine main gearbox and alternator. engine generator and alternator. engine N1 spool and alternator.

When sanding carbon brushes (12.10). sand the brushes only in the direction of rotation. sand the brushes only in the counter direction of rotation. direction of sanding is not important.

single phase motors are (18.2). low power motors. low torque motors. low speed motors.

Color code of a resistor tells us the (7.7). resistance value of the resistor. conductivity value of the resistor. voltage value of the resistor.