Questions and Answers
The heat loss inside a straight conductor is 60J upon applying current I for 5s. If the resistance of the conductor is decreased to half, and the same current is applied for 5s, what will be the heat dissipation?
Why do we use power factor correction devices?
If the rotor of an induction motor is rotating at synchronous speed, what is the torque?
The underground cable is laid in a marine environment at system voltage A. What shall be the design of the cable insulation?
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Cable length is 1000m, time of returning signal is 9.43µsec. What is the speed of wave in the cable?
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An antenna has an effective aperture of 10m². What additional information is required to determine the amplifier power?
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A 10HP single phase motor, 0.8 PF, 240V, Efficiency = 0.6. What is the current?
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Which of the following is not an opportunity to do the project?
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For the shown block diagram, what is the dumping ratio O/P / I/P = U/R where S = 1?
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An alternator is operating at __________ for capacitive loads.
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The minimum time to complete the project is:
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A superheterodyne AM receiver within an intermediate frequency (IF) of 455 kHz is to be tuned to listen to a station at 540 kHz. What tuning frequency is used in the local oscillator?
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For which of the following topologies can 10BaseT not be used without additional hardware conversion?
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High voltage windings of a transformer have _________ resistivity than the low voltage side.
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ACR of conductor has 7 steel wires and 25 aluminum wires can be specified as:
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The output D in the circuit is:
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The equivalent circuit of induction machine at no load is the same as that of the transformer but with:
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Which of these is not a rule of interaction?
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Within the battery, conventional current flow is:
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Activity on the arrow needs to use dummy activities to avoid precedence problem that can happen due to:
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What is the average value of signal v(t) = 5 sin(377t)?
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A 3 phase transformer, 25MVA, 66-12.47kV, delta-wye connected, 8 percent impedance. On the 100 MVA, per unit impedance is most nearly:
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What type and magnitude of resistance is required for the voltage range 0-100V?
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The offset of a particular segment varies from:
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The power gain of 30dB is equivalent to which amplification factor?
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Study Notes
Alternators and Motors
- Alternator Over Excitation: Operating in a leading power factor.
- Synchronous Motor Over Excitation: Also operates in a leading power factor.
- Induction Motor Torque at Synchronous Speed: The torque is zero.
Antennas and Capacitors
- Micro Antenna: Refers to a short antenna.
- Capacitance Calculation: For three 30µF capacitors in a star formation, the capacitance between two terminals is around 15µF.
Project Management
- Fast Track Scheduling Purpose: To minimize future cost increases rather than just reducing construction costs.
- Fast Tracking Defined: Initiating a project before completing the design phase.
- Float in Project Management: Refers to the amount of time that a task can be delayed without affecting the overall project timeline.
Signal and Systems
- Digital Telecommunication: Connection-oriented service is best provided by technologies such as ATM.
- Wattage Calculation: For an AC current scenario, the formula used involves both DC and AC components, yielding wattage outcomes based on effective current.
Electrical Principles
- Unit of Conductance: The unit is called mho.
- Conductance of Circuit: Noted for resistors in combinations such as series and parallel.
- Transformer Saturation: Results in high efficiency and significant no-load losses.
Filters and Feedback
- Use of Filters: High pass filters are used to eliminate DC offset.
- Feedback in Amplifiers: Negative feedback reduces gain but enhances stability and linearity of an amplifier.
Zener Diode and Electrical Components
- Function of Zener Diode: Primarily used for voltage regulation.
- Power Requirements: Calculations for supply resistors and diode power ratings consider variations in conditions such as load current.
Current and Resistance
- Current Rating in a Circuit: Defined based on voltage and resistance using Ohm’s law.
- Resistivity Comparison: High voltage side transformers typically have higher resistivity than low voltage sides.
Operational Characteristics
- Voltage Gain without Feedback: A 9% feedback reduces the apparent gain of the amplifier.
- Induction Motor Braking: Methods include regenerative and dynamic braking techniques to reduce the stop time effectively.
Miscellaneous Electrical Concepts
- VSWR (Voltage Standing Wave Ratio): Indicates the measure of efficiency in a transmission line. Higher ratios signify mismatched impedances.
- Heat Loss in Conductors: Describes energy loss proportional to the square of the current and resistance.
Project Scope and Management
- New Scope of Work: Engineers should inform their supervisors about new projects not included in initial scopes before proceeding.
- Rating of Cable Insulation: Must consider environmental factors for marine applications.
Important Equations
- H (Magnetic Field): H = I / (2πr) defines field intensity from a current-carrying conductor.
- Power Consumption in Embedded Systems: Typically noted around 10-80% depending on system requirements.
Resources in Electrical Systems
- Resistor Combinations: Understanding parallel vs. series resistances will yield different equivalent resistances.
- Signal Amplification in Wireless Systems: A low-noise amplifier is essential for enhancing weak received signals effectively.
This summary captures key concepts and principles, providing a concise overview for study in electrical and electronic engineering without overwhelming detail.### AM Receiver Tuning Frequency
- For a super heterodyne AM receiver with an IF of 455 kHz tuned to a station at 540 kHz, the local oscillator frequency is 995 kHz.
10BaseT Topology Compatibility
- 10BaseT cannot be used with a Bus topology without additional hardware conversion. It is compatible with Star, Tree, and Point-to-Point topologies.
Transformer High Voltage Windings
- High voltage windings of a transformer have higher resistivity compared to low voltage windings.
ACR of Conductors Specification
- A conductor with 7 steel wires and 25 aluminum wires is specified as 7/25.
Circuit Output Expression
- The output D in the circuit can be expressed as (A+B)(B+C).
Speed of Wave in Cable
- For a cable length of 1000m with a return signal time of 9.43 µsec, the speed of wave propagation in the cable can be calculated using the formula speed = distance/time.
Induction Machine Equivalent Circuit
- The equivalent circuit of an induction machine at no load is the same as that of a transformer with an open circuited secondary.
Rules of Interaction
- Etiquette, Morals, Communication, and Ethics are considered rules of interaction; "Law" is not typically included.
Battery Current Flow
- Within a battery, conventional current flows from the positive electrode to the negative electrode.
Precedence Problem in Activities
- Dummy activities are needed to avoid precedence problems that occur due to burst activities.
Average Value of a Signal
- The average value of the signal v(t) = 5 sin(377t) is approximately 3.2V.
3-Phase Transformer Impedance Calculation
- For a 25MVA, 66-12.47kV delta-wye connected transformer with 8% impedance, the per-unit impedance on a 100 MVA base is approximately 0.32.
Resistance Requirements in Circuit
- To achieve a voltage range of 0-100V, a series resistance of 1M ohm is required based on the provided hint.
Offset Variations
- The offset of a particular segment can vary from 0000H to FFFFH.
Power Gain and Amplification Factor
- A power gain of 30 dB corresponds to an amplification factor of 1000, calculated using the formula dB = 10 log(x).
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Description
This quiz covers fundamental concepts in electrical and electronic engineering, focusing on topics such as alternator excitation and synchronous motor operation. Test your knowledge on power factors and other essential principles in electrical systems. Ideal for students preparing for exams or professionals refreshing their understanding.
