Câu 1:
A DC circuit containing a total resistance of 100 ohms has a current flow of 250 mA. The power dissipated in the circuit is?
- a) 0.4 W
- b) 5 W
- c) 6.25 W
Câu 2:
A series resonant circuit consists of
- a) A coil and a capacitor connected in parallel
- b) A coil and a capacitor connected in series
- c) Tow coils and a capacitor connected in series
Câu 3:
Electromotive force is measured in
- a) Watts
- b) Ohms
- c) Volts
Câu 4:
The symbol for frequency is
Câu 5:
kilohm resistor has the following color code
- a) Yellow, violet, orange
- b) Orange, violet, red
- c) Red, orange, yellow
Câu 6:
An electric current is a flow of
- a) Electrons from a positively charged area to a negatively charged area
- b) Protons from a positively charged area to a negatively charged area
- c) Electrons from a negatively charged area to a positively charged area
Câu 7:
A sine wave has 10 voltage the peak value. What is RMS value?
- a) 14,14 V
- b) 7.07 V
- c) 10 V
Câu 8:
Two inductor coils in very close proximity; If the angle is 0 degree the magnetic flux which is generated by coil 1 will hit coil 2 in an optimal way. Coil 2 will have:
- a) A no voltage.
- b) The maximum possible voltage
- c) A lower voltage
Câu 9:
A heating device applied to 240 V consumes 3 A. What is the resistance?
Câu 10:
The total current flowing in a circuit of 200 lamps in parallel, each of a resistance of 400 ohm and connected across an input of 100 volts is
- a) 25 amps
- b) 40 amps
- c) 50 amps
Câu 11:
The symbol for inductance is
Câu 12:
How batteries are connected to constantly remain voltage?
- a) Series
- b) Parallel
- c) Perpendicular
Câu 13:
What is the potential difference of a circuit which has a 40mA current and a 1 kilo-ohm resistance?
Câu 14:
A transformer is used to supply four motors. Each motor gives a power of 5 kW. The power factor of the motors is 0.9. What is the minimum nominal power output of the transformer?
- a) 20 W
- b) 25 W
- c) 22,22 W
Câu 15:
The induced voltage increases proportional to:
- a) Magnetic field strength, speed of movement and the length of the conductor
- b) Speed of movement, the length of the conductor
- c) Magnetic field strength, speed of movement
Câu 16:
Commutating poles are connected
- a) In parallel with the armature and hence oppose the armature cross field
- b) In series with the armature and hence oppose the armature cross field
- c) In series with the armature and stator
Câu 17:
Three 12 µ(micro)F capacitors are in series. The total capacitance is
- a) 12 µ(micro)F.
- b) 36 µ(micro)F.
- c) 4 µ(micro)F.
Câu 18:
Which material is known to have low specific resistance?
- a) Copper
- b) Wool
- c) Plastic
Câu 19:
A coil that has an effective resistance of 12 Ohms and is applied to an AC voltage of 36 V at 50 Hz has a current consumption of 1 A. Calculate the reactive voltage
- a) 25 V
- b) 33,9 V
- c) 40 V
Câu 20:
What will happen when rubbing glass rod and silk?
- a) Nothing happens
- b) Glass rods receive electrons and become negatively charged
- c) Glass rods give up electrons and become positively charged
Câu 21:
A pure capacitor, inductor and resistor are connected in series and the voltage drops across each are 10V and the total current flowing in the circuit is 1A. How much true power is the circuit consuming?
Câu 22:
The direction of the induced voltage depends on
- a) The movement of the magnetic field
- b) The movement direction as well as the direction of the magnetic field
- c) The voltage applied
Câu 23:
When belonging to the galvanic cell, primary cells are knowns as
- a) Batteries
- b) Heat supply
- c) Electromagnetic field
Câu 24:
An AC transformer converts a voltage of 220 V to 12 V. The secondary coil has 100 turns. How many turns must the primary winding have?
Câu 25:
An ideal coil with an inductance of L = 200 mH is applied to an AC voltage of U = 220, f = 50 Hz, What current builds up?
- a) 3,5 A
- b) 0.291666666666667
- c) 35 A
Câu 26:
How many amperes will a 28-volt generator be required to supply to a circuit containing five lamps in parallel, three of which have a resistance of 6 ohms each and two of which have a resistance of 5 ohms each?
- a) 25.23 amperes
- b) 1 amperes
- c) 1.1111 amperes
Câu 27:
What is thermocouple application for?
- a) Thermocouples are used to measure temperatures (temperature range from−200° C to 2300° C) e.g. for remote measurements of temperatures at hard to reach places, e.g. ovens and windings.
- b) Thermocouples are used to measure temperatures (temperature range from−200° C to 2300° C). In aviation, thermocouples are mainly used to measure exhaust gas temperatures of engines.
- c) Thermocouples are mainly used to measure exhaust gas temperatures of engines
Câu 28:
What is the main function of photocells?
- a) Provide heat for conductor
- b) Generators of electrical voltage
- c) Produce energy for transmitting voltage
Câu 29:
If the voltage across a resistor is doubled
- a) The current is halved
- b) The current is doubled
- c) The current is tripled
Câu 30:
What does every battery generally contain?
- a) Plates and an acid which has a certain resistance
- b) Electromagnetic field
- c) Surplus voltage and current
Câu 31:
Which of these will cause the resistance of a conductor to decrease
- a) Decrease the length or increase the cross-sectional area
- b) Decrease the length or the cross-sectional area
- c) Increase the length or decrease the cross-sectional area
Câu 32:
A transformer has an input voltage of 220 V AC. The self-induced voltage in the primary coil is 215.5 V. It opposes the input voltage. In the primary coil, the resistance of the windings is 3 Ω. What is the current without self-induced voltage? This will happen when the voltage is a DC voltage.
- a) 71,6A
- b) 72,5A
- c) 73,3A
Câu 33:
Which statement is correct?
- a) Platinum is an example of a ferromagnets Material
- b) Platinum is an example of a paramagnetic material
- c) Platinum is an example of a diamagnets Material
Câu 34:
The RMS power is calculated by
- a) Multiplying the RMS voltage V with the RMS current I
- b) Multiplying the Upeak voltage V with the RMS current I
- c) Multiplying the RMS voltage V with the Ipeak
Câu 35:
Which statement is correct?
- a) Zinc is an example of a ferromagnets Material
- b) Zinc is an example of a paramagnetic material
- c) Zinc is an example of a diamagnets Material
Câu 36:
Using Ohm's law
- a) Current is directly proportional to the voltage
- b) Current is inversely proportional to the resistance
- c) Resistance directly proportional to the voltage
Câu 37:
The formula for resistance in series is
- a) RT = R1 + R2 + R3...RN
- b) RT= R1 x R2 x R3...RN
- c) 1/RT= 1/ (R1 x R2 x R3 ...RN)
Câu 38:
The series−wound machine basically consists of
- a) The stator with the excitation winding, the rotor with the armature winding and the carbon brushes
- b) The stator with the excitation winding, the rotor with the armature winding
- c) The rotor with the armature winding, the carbon brushes
Câu 39:
When the resistors are connected in series, the total resistance will be
- a) R= R1+R2+R3+…
- b) R=R1xR2xR3x…
- c) R= (R1xR2xR3x…)/(R1+R2+R3+…)
Câu 40:
The reactive power is measured in
Câu 41:
The power in a circuit when voltage and resistance is given can be found by?
- a) U*R
- b) U*U*R
- c) U*U / R
Câu 42:
Of the following which pair of materials would most readily become magnetized?
- a) Iron and steel.
- b) Copper and steel.
- c) Nickel and bronze.
Câu 43:
The symbol for the resonance frequency is
Câu 44:
If the distance between the two plates of a capacitor is reduced, what will be the effect?
- a) Capacitance increases.
- b) Capacitance decreases.
- c) Capacitance is unaffected.
Câu 45:
Coulomb’s Law is
- a) About the force electrical charges have on each other
- b) About the force molecule charges have on each other
- c) About the Energy electrical charges have on each other
Câu 46:
The AC generators of airplanes supply an AC voltage with a frequency of 400 Hz. How many pole pairs are necessary in a generator of a B737 which is driven at 6000 rpm?
Câu 47:
An ideal coil with an inductance of L = 200 mH is applied to an AC voltage of U = 220, f = 50 Hz, What is the inductive reactance?
- a) 31,4 Ω
- b) 6,28 Ω
- c) 62,8 Ω
Câu 48:
Which direction will the electron of the conductor be caused to deflect during induction process?
- a) Lateral
- b) Longitudinal
- c) Freely move
Câu 49:
Peak−to−peak value means:
- a) Negative maximum value of a sine curve
- b) Positive maximum value of a sine curve
- c) The value measured between positive maximum value and negative maximum value of a sine curve
Câu 50:
The turns ratio of transformer is calculated with this formula
Câu 51:
What is used to compare the "weight" of the resistor?
- a) Wheatstone bridge
- b) Millivoltmeter
- c) Ammeter
Câu 52:
A piezoelectric device generates electricity through
- a) Pressure
- b) Friction
- c) Light
Câu 53:
The symbol for reactive power is
Câu 54:
What is the combined value of resistances of 4 ohm and 6 ohm connected in parallel?
- a) 24 ohms
- b) 2.4 ohms
- c) 0.24 ohms
Câu 55:
If the resistance of an electrical circuit is increased
- a) The current will increase
- b) The voltage will increase
- c) The voltage will decrease
Câu 56:
A coil that has an effective resistance of 12 Ohms and is applied to an AC voltage of 36 V at 50 Hz has a current consumption of 1 A. Calculate the impedance.
Câu 57:
What is the most popular combination of batteries?
- a) Copper-oxygen
- b) Lead-Helium
- c) Zinc-carbon
Câu 58:
How many items the induced voltage depends on
Câu 59:
The voltage in a series circuit
- a) Is the same in each component
- b) Is different in each component
- c) Is less than it would be in a parallel circuit
Câu 60:
What charge does the nucleus of an atom possess?
- a) Positive
- b) Negative
- c) Neutral
Câu 61:
A potentiometer varies
- a) Voltage
- b) Current
- c) Resistance
Câu 62:
In a coil with an inductive reactance of XL = 30 Ohm a current of I = 2 A flows. What voltage occurs on the inductive reactance?
Câu 63:
Which of the following materials is easiest to magnetize?
- a) Copper
- b) Iron
- c) Nickel
Câu 64:
The amount of charge depends on
- a) The plate size, the distance between the plates and on the applied voltage
- b) The plate size and the distance between the plates
- c) The distance between the plates and on the applied voltage
Câu 65:
If 2 coulombs flowed through a circuit in 2 seconds, the circuit would have
- a) 2 volts PD
- b) 2 amps
- c) 1 amp
Câu 66:
In series resonance, which are condition for resonances?
- a) XL = XC
- b) UL = UC
- c) XL = XC; UL = UC
Câu 67:
Ohm's law states that
- a) Voltage= current divided by resistance
- b) Resistance= current divided by voltage
- c) Current= voltage divided by resistance
Câu 68:
The process of breaking up crystal bonding is caused by
- a) Protons
- b) High voltage
- c) Photons
Câu 69:
Three capacitors 10 microfarads, 10 nanofarads and 10 millifarads are connected in parallel. What is the total capacitance?
- a) 10.01001 millifarads.
- b) 111 millifarads.
- c) 1.001001 millifarads.
Câu 70:
The mass of an atom is mainly focus on the?
- a) Electrons
- b) Protons
- c) Protons and neutrons
Câu 71:
What is the main advantage of connecting power sources in series?
- a) Increase induction
- b) Increase the voltage
- c) Increase the resistance
Câu 72:
How many part the rotor of a electrical machine has?
Câu 73:
Which statement is correct?
- a) The capacity depends on area of the plates, Distance between the plates
- b) The capacity depends on area of the plates, Distance between the plates, Dielectric
- c) The capacity depends on distance between the plates, Dielectric
Câu 74:
The symbol for capacitive reactive power is
Câu 75:
K Ohm resistor with a 10% tolerance has the following color code:
- a) Orange, violet, red, gold
- b) Red, orange, yellow, silver
- c) Yellow, violet, orange, silver
Câu 76:
A circuit has a current flow of 6A. If the voltage is trebled, the new current will be.
Câu 77:
What is each atom made up of the following components?
- a) Protons, Neutrons, Electrons
- b) Protons, Core, Electrons
- c) Nucleus, Neutrons, Electrons
Câu 78:
How many valence electrons with L shell?
Câu 79:
Which methods are applied to control the speed of DC machines in practice?
- a) Voltage control and Field Control
- b) Voltage control
- c) Field Control
Câu 80:
V battery supplies a resistive load of 10 ohms for 1 minute. What is the power supplied?
- a) 100 W
- b) 10 VA
- c) 10 W
Câu 81:
What are main functions of proximity switches?
- a) Monitor the position of the landing gear and the undercarriage door.
- b) To measure deflect angle of control surface
- c) To measure deflect angle of landing gear
Câu 82:
The stationary part of a electrical machine is
- a) Magnetic flux
- b) Stator
- c) Rotor
Câu 83:
The symbol for apparent power is
Câu 84:
The magnetic field strength is
Câu 85:
Diamagnetic materials have a permeability
- a) Which is much higher than the permeability of the vacuum.
- b) Which is much smaller than the permeability of the vacuum
- c) Which is nearly the same as the permeability of air or the vacuum
Câu 86:
The symbol for the magnetic flux density is:
Câu 87:
In the circuit shown the 24 volt battery has the ammeter indicates a current of 12 amperes. The value of the load resistance is.
- a) 2 ohms
- b) 4 ohms
- c) 8 ohms
Câu 88:
What is the definition of Elementary Charge?
- a) Every electron carries a negative charge, every proton carries a positive charge. Both have the smallest charge existing,
- b) Every Proton carries a negative charge, every Neutron carries a positive charge. Both have the smallest charge existing,
- c) Every electron carries a positive charge, every proton carries a negative charge. Both have the smallest charge existing,
Câu 89:
Having two conductors parallel, if the direction of the current running the conductors is different:
- a) The wires attract
- b) The wires attract then repel
- c) The wires repel
Câu 90:
A transformer has an input voltage of 220 V AC. The self-induced voltage in the primary coil is 215.5 V. It opposes the input voltage. In the primary coil, the resistance of the windings is 3 Ω. What is the no-load current of the transformer?
Câu 91:
1 Volt is produced when a current of 1 Amp per second is varied in a coil'. This is a definition of
- a) 1 Henry
- b) 1 Ampere per metre
- c) 1 Coulomb per second
Câu 92:
The symbol for the magnetic field strength is
Câu 93:
The symbol for the magnetomotive force is
- a) Dental
- b) Theta
- c) Beta
Câu 94:
Total resistance in parallel for R1 and R2 is
- a) 1/RT = (R1 x R2) ÷ (R1 + R2)
- b) RT = 1/R1 + 1/R2
- c) 1/RT = 1/R1 + 1/R2
Câu 95:
What must you do to make a 3 F capacitor circuit into a 2 F circuit?
- a) Put a 2 F capacitor in parallel.
- b) Put a 6 F capacitor in series.
- c) Put a 1 F capacitor in series.
Câu 96:
The magnetomotive force is measured in
Câu 97:
What is the reason for the good conductivity of metal?
- a) Metal is the high mobility of its electrons
- b) Metal is the low mobility of its electrons
- c) Metal is an arrangement of atoms with 8 electrons in the valence orbit
Câu 98:
The synchronous machines have
- a) A constant ratio of rotation speed and frequency.
- b) A constant ratio of rotation speed
- c) A constant of frequency.
Câu 99:
Ferromagnetic materials have a relative permeability
- a) Which is much higher than the permeability of the vacuum.
- b) Which is much smaller than the permeability of the vacuum.
- c) Which is nearly the same as the permeability of the vacuum.
Câu 100:
The current flowing through a circuit can be increased to four times its original value by
- a) Doubling the applied voltage and doubling the resistance
- b) Doubling the applied voltage and halving the resistance
- c) Halving the applied voltage and halving the resistance
Câu 101:
Two inductor coils in very close proximity; If the angle is 45 degree the magnetic flux which is generated by coil 1 will hit coil 2 in an optimal way. Coil 2 will have:
- a) A no voltage.
- b) The maximum possible voltage
- c) A lower voltage
Câu 102:
In a DC motor, the stator's magnetic field, due to armature reaction, moves
- a) Into alignment with the GNA
- b) In the same direction of rotation of the armature
- c) In the opposite direction of rotation of the armature
Câu 103:
The apparent power is measured in
- a) Var
- b) KW
- c) Volt-Ampere [VA]
Câu 104:
Which statement is correct?
- a) Cobalt is an example of a ferromagnets Material
- b) Cobalt is an example of a paramagnetic material
- c) Cobalt is an example of a diamagnets Material
Câu 105:
Lead Batteries can be recharged by using
- a) AC current
- b) DC current
- c) Both AC current and DC current
Câu 106:
What are the main material used for NTC resistors?
- a) Platinum, nickel, cobalt
- b) Platinum, copper, iron, nickel
- c) Aluminium, copper, cobalt
Câu 107:
Which statement is correct?
- a) A capacitor with double the area and double the dielectric thickness will have double the capacitance.
- b) A capacitor with double the area and double the dielectric thickness will have the same capacitance.
- c) A capacitor with double the area and double the dielectric thickness will have half the capacitance.
Câu 108:
Voltage is generated by
- a) The free flow of neutron
- b) The heat between electron and proton
- c) The separation of charges
Câu 109:
Paramagnetic materials have a permeability
- a) Which is much higher than the permeability of the vacuum.
- b) Which is much smaller than the permeability of the vacuum.
- c) Which is nearly the same as the permeability of air or the vacuum
Câu 110:
What effect do the electrons of one atom have upon the electrons of another atom?
- a) They repel each other
- b) They attract each other
- c) They have no effect on each other
Câu 111:
Two inductive coils are placed in close proximity with each other at 90 degrees. The number of flux linkages is
- a) Maximum negative
- b) 0
- c) Maximum positive
Câu 112:
A primary cell
- a) Can be recharged
- b) Cannot be recharged
- c) Can be recharged but in a few times
Câu 113:
What is the meaning of peak value?
- a) The positive maximum value which a sine curve can assume
- b) The positive or negative maximum value which a sine curve can assume
- c) The negative maximum value which a sine curve can assume
Câu 114:
Which statement is correct?
- a) The stator of a DC machine has a steel ring (yoke), the main poles made of sheet metal with pole core
- b) The stator of a DC machine has the main poles made of sheet metal with pole core, pole shoe and the excitation winding.
- c) The stator of a DC machine has a steel ring (yoke), the main poles made of sheet metal with pole core and pole shoe and the excitation winding.
Câu 115:
According to Faraday the induced voltage is calculated by
- a) The change of the number of windings
- b) The magnetic flux within a certain span of time
- c) The change of the magnetic flux within a certain span of time
Câu 116:
A coil that has an effective resistance of 12 Ohms and is applied to an AC voltage of 36 V at 50 Hz has a current consumption of 1 A. Calculate the inductive reactance.
- a) 35 Ω
- b) 40 Ω
- c) 33,9 Ω
Câu 117:
A lamp has eight light bulbs. They have a power consumption of 50 watts each. The voltage is 230 volts, What is the current in the lamp?
- a) 1,74 A
- b) 2,74 A
- c) 0.125
Câu 118:
How much power must a 24-volt generator furnish to a system which contains the following series loads? 5 ohm, 3 ohm and 12 ohm
- a) 42 W
- b) 28.8 W
- c) 45 W
Câu 119:
Which statement is correct?
- a) Aluminium and platinum are ferromagnets
- b) Aluminium and platinum are paramagnets
- c) Aluminium and platinum are diamagnets
Câu 120:
An electric current is a flow of
- a) Electrons from a positively charged area to a negatively charged area
- b) Protons from a positively charged area to a negatively charged area
- c) Electrons from a negatively charged area to a positively charged area
Câu 121:
The inductance is measured in
- a) µ (mu)
- b) Henry (H)
- c) Φ (phi).
Câu 122:
Photocells are also regarded as
- a) Opto-electronic components
- b) Transducers
- c) Capacitors
Câu 123:
ohm resistor carries a 3 amp current. What is the power dissipated?
- a) 500 W
- b) 4.5 kW
- c) 5 kW
Câu 124:
If the magnetic wheel of a bipolar device (one pole pair) rotates 50 times per second,
- a) An AC with a frequency of f = 5 Hz is generated
- b) An AC with a frequency of f = 500 Hz is generated
- c) An AC with a frequency of f = 50 Hz is generated
Câu 125:
To find which end of an electromagnet is the north pole, use the
- a) Fleming's Left Hand Rule.
- b) Cork Screw Rule.
- c) Right Hand Clasp Rule.
Câu 126:
The symbol for permeability is
- a) Θ (theta)
- b) µ (mu)
- c) Φ (phi)
Câu 127:
Which requires the most electrical power during operation?
- a) A 12-volt motor requiring 8 amperes
- b) Four 30-watt lamps in a 12-volt parallel circuit.
- c) Two lights requiring 3 amperes each in a 24volt parallel system.
Câu 128:
What is the power dissipated in a 500 ohm resistor with a 3A flow?
- a) 4.5 kW
- b) 1.5 kW
- c) 750 kW
Câu 129:
Which types of material contain positive charges?
- a) Nylon, Silver, Copper, lead
- b) Sulfur, Polyester, Silicon, Celluloid
- c) Glass, human hair, silk, lead, aluminium
Câu 130:
When different rated capacitors are connected in parallel in a circuit, the total capacitance is?
- a) Less than the capacitance of the lowest rated capacitor.
- b) Equal to the capacitance of the highest rated capacitor.
- c) Equal to the sum of all the capacitances.
Câu 131:
In a circuit containing three resistors of equal value connected in parallel, one resistor goes open circuit. The current in the other two resistors will
- a) Increase
- b) Decrease
- c) Remain the same
Câu 132:
What happens during the breaking up process of the crystal bonding?
- a) Current and electromagnetic are born
- b) An electron and hole are released
- c) Nothing happens
Câu 133:
What is definition of proximity switches?
- a) A target which connected to the sensor unit.
- b) A sensor which can detect an object coming nearer by the change of the magnetic field
- c) A sensor which can detect an object coming far by the change of the magnetic field
Câu 134:
A capacitor with a capacitance with C = 10 µF is connected to an AC voltage source with U = 220 V, f = 50 Hz, What value is the current input of the capacitor?
- a) 3,46 A
- b) 0,692 A
- c) 0,173 A
Câu 135:
The number of windings of the transformer's output coil is
Câu 136:
Generally, a transformer consists of:
- a) Two coils and an iron core
- b) Two cores and a coil
- c) Two cores and an iron core
Câu 137:
The rotating part of a electrical machine is
- a) Magnetic flux
- b) Stator
- c) Rotor
Câu 138:
The increase in the temperature of the NTC resistors will lead to
- a) The increase in the conductivity of the material
- b) The increase in electromotive force
- c) The increase in electromagnetic force of the material
Câu 139:
Which statement is correct?
- a) Current transformers allow the measurement of AC currents without breaking the current−carrying leads
- b) Current transformers allow the measurement of AC voltage without breaking the current−carrying leads
- c) Current transformers allow the measurement of DC voltage without breaking the current−carrying leads
Câu 140:
Having two conductors parallel, if the direction of the current running the conductors is the same:
- a) The wires attract
- b) The wires attract then repel
- c) The wires repel
Câu 141:
What type of current exist in conductive liquids?
- a) Electron current
- b) Ion and electron currents
- c) Ion currents
Câu 142:
Design and Principle of Operation thermocouples?
- a) Two different metals (e.g. copper and iron) are connected at one end, a voltage is generated between the two free ends when temperatures increase
- b) Different metals have different numbers of free electrons and therefore a different electron density.
- c) Different metals have different numbers of free electrons and therefore a different electron density; Two different metals (e.g. copper and iron) are connected at one end, a voltage is generated between the two free ends when temperatures increase
Câu 143:
The short circuit voltage of a transformer is
- a) A reference for the change of the output voltage when the load increases
- b) A reference for the change of the output voltage when the load decreases
- c) A reference for the change of the output voltage when the load no change
Câu 144:
If voltage is 100V, resistance is 25 ohms, what is the current?
Câu 145:
The secondary winding of a transformer with 60 turns consumes a current of 10 A. How many amperes consumes a primary winding with 1200 turns?
Câu 146:
A capacitor with a capacitance with C = 10 µF is connected to an AC voltage source with U = 220 V, f = 50 Hz, What value is the capacitive reactance of the capacitor?
- a) XC= 318 Ω
- b) XC= 381 Ω
- c) XC= 636 Ω
Câu 147:
Which of the following is 1Amp?
- a) 1000 A
- b) 1000 kA
- c) 1000 mA
Câu 148:
An electric current is
- a) A surplus of free electron
- b) An excitement of electrons in a metal
- c) An ordered flow of electrons
Câu 149:
Six resistors each of 6 ohms would be
- a) 36 ohms in parallel
- b) 1 ohm in series
- c) 1 ohm in parallel
Câu 150:
1 Ampere will equal to?
- a) 6.25 x 10^15 electrons per second.
- b) 6.25 x 10^21 electrons per millisecond.
- c) 6.25 x 10^18 electrons per second.
Câu 151:
A aircraft passenger’s mass is 80 kg. The speed of the aircraft is 864 km/h. How much kinetic Energy?
- a) 2304 kNm
- b) 2403 kNm
- c) 2504 kNm
Câu 152:
What is the ideal condition for metals to conduct in PTC resistors
- a) High temperature
- b) High current and voltage
- c) Low temperature
Câu 153:
A coil that has an effective resistance of 12 Ohms and is applied to an AC voltage of 36 V at 50 Hz has a current consumption of 1 A. Calculate the effective voltage.
- a) 11,88 V
- b) 12 V
- c) 24 V
Câu 154:
In general, increasing the cross sectional area of an electrical cable
- a) Enables it to carry more voltage
- b) Enables it to carry more current
- c) Increase its resistance
Câu 155:
Where can secondary cells be used?
- a) Cars, aircraft, laptop
- b) Thermometer
- c) Thyristor
Câu 156:
The voltage of a secondary cell is
- a) Determined by the active materials on the plates
- b) Determined by the number of plates
- c) Determined by the area of the plates
Câu 157:
A sine wave has 5 amps RMS value. What is the peak value?
- a) 7.07 amps.
- b) 6.37 amps.
- c) 10 amps.
Câu 158:
A band −stop filter consists of
- a) A high−pass filter and a low−pass filter in parallel
- b) A high−pass filter and a low−pass filter in series
- c) Tow high−pass filters in parallel
Câu 159:
The number of windings of the transformer's input coil is
Câu 160:
The resitance given by Ohm's Law
- a) Does not depend on the voltage applied
- b) Depends on the current applied
- c) Depends on voltages and currents applied
Câu 161:
The 4th colored band on a resistor represents the
- a) Tolerance
- b) Multiplier
- c) Reliability or temperature coefficient
Câu 162:
An electric motor has a power consumption of 500 W (according to the nameplate) and the efficiency is 90 %. Therefore the power delivered at the shaft is?
- a) 400 W
- b) 450 W
- c) 500 W
Câu 163:
A band−pass filter consists of
- a) A high−pass filter and a low−pass filter in parallel
- b) A high−pass filter and a low−pass filter in series
- c) Tow high−pass filters in parallel
Câu 164:
The voltage rating of a capacitor is?
- a) The min voltage required to charge.
- b) The normal operating voltage
- c) The max voltage that can be constantly applied
Câu 165:
The peak power is calculated by:
- a) Multiplying the peak voltage Upeak with the peak current Ipeak
- b) Average the peak voltages Upeak
- c) Average the peak current Ipeak
Câu 166:
When two capacitors are connected in series.
- a) The charge stored on each is inversely proportional to the voltage across it.
- b) The charge stored on each is the same.
- c) The charge stored on each is directly proportional to its capacitance.
Câu 167:
Which statement is correct?
- a) The DC shunt−wound motor is used whenever a constant speed at various loads is required,
- b) The DC shunt −wound motor is used whenever a constant speed at various loads is not required,
- c) The DC shunt−wound motor is used whenever a high power is required,
Câu 168:
Two inductor coils in very close proximity; if one of the coils is rotated 90 degrees slowly away from the other the mutual inductance
- a) Decreases
- b) Remains the same
- c) Increases.
