Untitled Presentation

Multiple Choice

What is the definition of power in an electrical circuit?

• Power is the rate at which electrical energy is transferred by an electric circuit.

• Power is the total energy consumed by a circuit over time.

• Power is the voltage multiplied by the current in a circuit.

• Power is the resistance in a circuit.

Multiple Choice

What is the relationship between U_d and E_p in the given circuit?

• U_d = √3E_p

• E_p = √3U_d

• U_d = E_p

• All are incorrect

Multiple Choice

What does the following statement express about the voltage source?

• The voltage source can create a current in one direction only.

• The voltage source can create a current in both directions.

• The voltage source always changes according to load requirements.

• The voltage source has a fixed voltage regardless of the load.

Multiple Choice

In a circuit with RLC components, which formula is used to calculate the charge Q of a branch?

• Q = R I^2

• Q = -X_C I^2

• Q = (X_L - X_C)^2

• Q = X_L I^2

Multiple Choice

Cho một mạch điện ba pha có tải mắc hình sao (Y) bất đối xứng. Có dây truyền tính. Không xét trở kháng của đường dây truyền tải. Điện áp dây Ud = 380(V). Trở kháng phức của tải là Zp1 = 20 + j2(Ω), Zp2 = 30 + j3(Ω), Zp3 = 40 + j4(Ω). Công suất tác dụng của tải là

• P ≈ 5,2(kW)

• P ≈ 6,2(kW)

• P ≈ 7,2(kW)

• P ≈ 4,2(kW)

Multiple Choice

In the case of a synchronous machine, what is the significance of the rotor's magnetic field?

• It determines the speed of the machine

• It affects the efficiency of the machine

• It influences the torque produced

• All of the above

Open Ended

Describe the type of stator shown in the image below.

Multiple Choice

Which type of stator is represented in the image?

• Stator with 3 main poles and 3 auxiliary poles

• Stator with 6 poles

• Stator with 3 main poles and 3 auxiliary poles

• Stator with 6 poles

Multiple Choice

What is the relationship between the rotor speed (n) and the synchronous speed (n1) in a synchronous machine?

• n ≠ n1

• n > n1

• n < n1

• n = n1

Multiple Choice

What is the significance of the symbol shown in the image?

• It represents a type of transformer

• It indicates a core type of machine

• It shows a specific electrical component

• It denotes a type of circuit

Multiple Choice

In the diagram below, how does the current flow in the rotor circuit when the motor is running?

• A. Current flows from the rotor to the stator

• B. Current flows from the stator to the rotor

• C. Both are correct

• D. None of the above

Multiple Choice

A transformer operates with a power of 10kW at a primary voltage of 160V and a secondary voltage of 220V. What is the approximate current on the secondary side?

• A. 45A

• B. 44A

• C. 46A

• D. 43A

Multiple Choice

What type of electrical circuit is represented in the diagram below?

• A. Series circuit

• B. Parallel circuit

• C. Single-phase circuit

• D. Three-phase circuit

Open Ended

What is the relationship between points A and B in the given electric circuit?

Multiple Choice

Identify the correct statement regarding the power in an electric circuit.

• Power is always positive in an electric circuit.

• Power can be negative in an electric circuit.

• Power is independent of voltage and current.

• Power is only determined by the load.

Multiple Choice

Which of the following statements about the electric circuit is correct?

• The circuit must have a voltage source, load, and resistance.

• The circuit consists of a voltage source and load only.

• The circuit must have a voltage source and resistance only.

• The circuit can have multiple loads without a voltage source.

Multiple Choice

What is the correct expression for the frequency of a type of electric motor with the given parameters?

• n = 500(rpm)

• n = 600(rpm)

• n = 100(rpm)

• n = 250(rpm)

Multiple Choice

The voltage of the battery is 18 V. If the light bulb is replaced by one with one half the original resistance, which of the following will triple the current?

• Replace the battery with a battery voltage of 27 V.

• Replace the battery with a battery voltage of 12 V.

• Replace the battery with a battery voltage of 108 V.

• Replace the battery with a battery voltage of 3 V.

Multiple Choice

Which of the following is the correct answer regarding the transformer mentioned?

• Transformer with a primary winding and a secondary winding.

• Transformer with a primary winding and a tertiary winding.

• Transformer with a primary winding and a secondary winding, and a cooling part.

• Transformer with a primary winding, a core, and a cooling part.

Multiple Choice

What type of electric machine is described in the text?

• A type of electric machine based on the principle of electromagnetic induction from the interaction between coils.

• A type of electric machine based on the principle of electromagnetic induction from the interaction between coils that do not move relative to each other.

• A type of electric machine based on the principle of electromagnetic induction from the interaction between coils that move relative to each other.

• All are incorrect.

Multiple Choice

What is the value of the current I_p in the circuit shown?

• 7.1(A)

• 7.5(A)

• 7.7(A)

• 7.3(A)

Multiple Choice

What is the principle by which transformers operate?

• Electromagnetic induction

• Thermal induction

• Piezoelectric effect

• Capacitive coupling

Open Ended

The image below illustrates the principle diagram of which type of electric motor?

Multiple Choice

In the contribution of a single-phase motor, how many windings are connected to the power supply?

• 2 windings

• 1 winding

• 4 windings

• 6 windings

Multiple Choice

What type of rotor does the three-phase induction motor use?

• Rotor with 10 poles

• Rotor with 5 main poles, 5 auxiliary poles

• Rotor with 10 poles

• Rotor with 5 main poles, 5 auxiliary poles

Multiple Choice

Which of the following statements about the construction of the stator core is correct?

• The steel sheets are assembled with the technical sheets of the cylindrical shape, with large and thick edges.

• The steel sheets are assembled with the technical sheets of the circular shape, with large edges.

• The steel sheets are assembled with the technical sheets of the rectangular shape, with large edges.

• The steel sheets are assembled with the technical sheets of the cylindrical shape, with thin edges.

Multiple Choice

What is the frequency of the generated current if the rotor speed is 300 rpm?

• 30 Hz

• 20 Hz

• 40 Hz

• 50 Hz

Multiple Choice

How many poles does the motor in the diagram have?

• 8 poles

• 4 poles

• 2 poles

• 6 poles

Multiple Choice

What type of motor is represented in the diagram?

• Single-phase motor

• Three-phase motor

• DC motor

• Universal motor

Multiple Select

Which equations are correct?

• ε₁ - i₁R₁ - i₂R₂ = 0

• ε_{1 +} ε₂ + i₃R₃ - i₂R₂ = 0

• ε₁ - i₂R₁ - i₂R₂ = 0

• ε₁ - ε₂ - i₃R₃ + i₂R₂ = 0

Multiple Choice

Cho một mạch điện ba pha có tải mạch hình sao (Y) đối xứng. Không xét trở kháng của đường dây truyền tải. Điện áp dây Ud = 380(V). Trở kháng phức của tải là Zp = 2 - j2(Ω). Công suất phản kháng của tải là ___?

• -44,1(kVAr)

• -40,1(kVAr)

• -36,1(kVAr)

• -32,1(kVAr)

Fill in the Blank

Fill in the blank: The primary function of a transformer is to change the ___ of electrical energy.

Open Ended

In the context of electrical circuits, what role does the transformer play?

Multiple Choice

Which of the following statements is true regarding the types of transformers?

• A transformer with a primary and secondary winding can be used to step up voltage.

• A transformer can only be used to step down voltage.

• Transformers can only operate with AC current.

• Transformers are not used in power distribution.

Multiple Choice

What is the shape of the cross-section of the transformer core when the transformer is subjected to pressure from different directions?

• Circle

• Rectangle

• Square

• Triangle

Multiple Choice

In the rotor of a single-phase motor, what is the relationship between the number of poles and the number of rotor slots?

• The number of poles is double the number of rotor slots

• The number of poles is equal to the number of rotor slots

• The number of poles is half the number of rotor slots

• The number of poles can be any value compared to rotor slots

Multiple Choice

In a three-phase induction motor, if the rotor does not rotate, what could be the reason?

• The rotor is not properly aligned

• The stator field is rotating too slowly

• The rotor is locked in place

• All of the above

Multiple Choice

A three-phase induction motor requires which condition to ensure proper operation?

• The rotor must have more poles than the stator

• The rotor must have fewer poles than the stator

• The stator poles must equal the rotor poles

• The rotor and stator poles must be equal

Multiple Choice

Calculate the current supplied to a single-phase motor with a power of 100W, voltage of 24V, and efficiency of η = 0.85. What is the current?

• I ≈ 5.0A

• I ≈ 4.7A

• I ≈ 4.8A

• I ≈ 4.9A

Multiple Choice

A three-phase induction motor has a pole number of p = 8. If the stator winding of the motor has a frequency of f = 50(Hz), what is the speed of the rotor?

• n = 355(rpm)

• n = 365(rpm)

• n = 375(rpm)

• n = 385(rpm)

Multiple Choice

What is the correct position of the rotor in the image?

• Position (b)

• Position (c)

• Position (d)

• Position (a)

Multiple Choice

Kirchoff's First Law states

• the sum of the currents entering any junction in an electric circuit must equal the sum of the currents leaving that junction

• the sum of the charges entering any junction in an electric circuit must equal the sum of the charges leaving that junction

• the sum of the emfs entering any junction in an electric circuit must equal the sum of the pds leaving that junction

• none of these

Multiple Choice

What is the core type of the transformer described in the image?

• A core that can only be magnetized externally

• A core that can be magnetized both externally and internally

• A core that can only be magnetized internally

• A core that cannot be magnetized

Multiple Choice

What type of transformer is described in the image?

• A transformer that can only handle single-phase voltage

• A transformer that can handle both single-phase and three-phase voltage

• A transformer that can only handle three-phase voltage

• A transformer that can handle both AC and DC voltage

Multiple Choice

What is the symbol shown in the image representing?

• Air core transformer

• Iron core transformer

• Ferrite core transformer

• Variable transformer

Multiple Choice

Which method is not used for controlling the speed of a unidirectional motor?

• Method of adjusting speed by changing the frequency

• Method of adjusting speed by changing the voltage

• Method of adjusting speed by changing the resistance

• All are incorrect

Multiple Choice

What type of current flows through the rotor windings of a three-phase electric motor?

• Rotating current

• Single-phase current

• A combination of both

• Direct current

Multiple Choice

What is the main purpose of the transformer casing in a transformer?

• To create an aesthetic design for the transformer

• To increase the rigidity of the transformer

• To reduce the weight of the transformer

• To increase the surface area for heat dissipation of the transformer

Multiple Choice

The diagram below represents the principle of operation of which type of electric motor?

• Single-phase motor

• Three-phase motor

• Synchronous motor

• Induction motor

Multiple Choice

How does the frequency f of the three-phase power supply affect the speed of the rotating magnetic field?

• Increasing f decreases speed and vice versa

• Changing f can adjust the speed of rotation

• No effect on the speed

• Changing f can maintain speed at certain levels

Multiple Choice

What type of stator is used in the design shown in the image?

• Stator with a single winding

• Stator with multiple windings

• Stator with a single winding, open type

• Stator with multiple windings, closed type

Multiple Choice

A transformer has a primary voltage of U_p = 200V and a secondary voltage of U_s = 220V. The current in the secondary circuit is I_s = 10A. What is the current in the primary circuit I_p?

• 11A

• 10A

• 9A

• 12A

Fill in the Blank

What is the frequency of the current supplied to the stator of the motor with a rotor speed of 300 rpm?

Multiple Select

Identify the correct part of the rotor that plays a role in the electric motor as shown in the diagram.

• A. Part (d) and (b)

• B. Part (a) and (b)

• C. Part (c) and (b)

• D. Part (c) and (d)

Multiple Choice

What method is used in the diagram to control the voltage of the electric motor?

• A. Method using a PWM controller

• B. Method using a variable resistor

• C. Method using a direct connection

• D. Method using a transformer

Multiple Choice

What is the formula for n in the context of the diagram shown?

• n = (Ux / (kg.φ)) - (Ry / (k7.kg.φ)).T

• n = (Ux / (kg.φ)) - (Ry / (k7.kg.φ)).T

• n = (√(k7.kg.Ux) / (kg)) * (1 / √(T)) - (Ry / kg)

• n = (Ry / (k7.kg.φ)).T

Multiple Choice

What is the value of the resistor labeled R in the third question?

• 222 MΩ ± 1%

• 22 MΩ ± 0.5%

• 2.22 MΩ ± 0.5%

• 220 Ω ± 1%

Multiple Choice

What is the value of the resistor labeled R in the second question?

• 10 kΩ ± 10%

• 0.01 kΩ ± 5%

• 100 Ω ± 5%

• 471 kΩ ± 10%

Multiple Choice

What is the value of the resistor labeled R33?

• 0.33 KΩ

• 33Ω

• 3.3Ω

• 0.33Ω

Multiple Choice

Variable resistors are:

• Carbon resistors

• thin film resistors

• cheap and easy to machine

• wire wound resistors

Multiple Choice

For the circuit shown, if Vcc = 12V, R1 = R2 = 1K, R3 = 2K, calculate Vout1 and Vout2.

• Vout1 = Vout2 = 6V

• Vout1 = 9V; Vout2 = 6V

• Vout1 = Vout2 = 4V

• Vout1 = Vout2 = 8V

Poll

How confident do you feel about this topic now?

• Very confident
• Somewhat confident
• Not confident