About this previous year paper
This document is a B.Tech Electrical Engineering Semester Examination question paper, designed for a total of 100 marks to be attempted within 3 hours. It thoroughly covers fundamental and applied concepts of basic electrical engineering, circuit theory, AC analysis, transformers, machines, resonance, measurement techniques, and power systems. The paper is divided into three structured sections—A, B, and C, ensuring a balanced evaluation of conceptual understanding, numerical ability, and analytical problem-solving skills.
SECTION – A (Short Answer Questions – 10 × 2 = 20 Marks)
This section includes ten short and direct questions, testing basic definitions and essential theoretical knowledge. Topics include:
Unilateral & bilateral elements used in circuit theory
Advantages of three-phase systems over single-phase supply
Reason behind calling series resonance “voltage resonance”
Meaning of acceptor and rejector circuits in AC networks
Need for damping torque in analog measuring instruments
Concept of phase sequence in three-phase systems
Methods to minimize hysteresis loss in transformers
Function of the commutator in DC generators
Names of motors suitable for constant-speed operation
Role of capacitors in ceiling fans for starting and phase splitting
This section evaluates core theoretical knowledge needed before moving to numerical and analytical questions.
SECTION – B (Numerical & Analytical Questions – 5 × 10 = 50 Marks)
Students must answer any five out of eight questions. These involve calculations, circuit analysis, derivations, and detailed conceptual explanations. Major topics include:
Network Analysis:
Solving for current using loop/mesh current method and verifying results using node voltage method.
Parallel AC Circuits:
Finding:
Current through each branch
Total current and power factor
Equivalent impedance
Drawing a phasor diagram
Power Factor:
Definition, causes of low power factor, effects on system efficiency, and methods of power factor improvement (capacitors, synchronous condensers, phase advancers).
Series RLC Circuit:
Given R = 10 Ω, L = 0.1 H, C = 8 μF, determining:
Resonant frequency
Q-factor
Bandwidth
Lower and upper half-power frequencies
Transformer Theory:
Discussing transformer losses (iron & copper), efficiency, and conditions for maximum efficiency.
Measuring Instruments:
Construction, working, advantages, and disadvantages of attraction-type moving iron instruments.
DC Machines:
A 20 kW, 250 V DC shunt machine problem to calculate:
Developed EMF when working as a generator
Developed EMF when working as a motor
Three-Phase Induction Motor:
Working principle, torque–slip characteristics, and explanation of operating, braking, and generating regions.
This section strengthens understanding of practical and theoretical aspects of AC/DC systems, machines, and instruments.
SECTION – C (Long Answer Questions – 2 × 15 = 30 Marks)
This section includes three detailed questions, and the student must attempt any two. These questions require in-depth derivations, numerical computations, and analytical reasoning.
Q3 — Maximum Power Transfer Theorem
Statement and proof of the theorem
Finding the value of load resistance R for maximum power transfer
Calculating maximum power for the given circuit
Q4 — Q-Factor, Bandwidth & Two-Wattmeter Method
Meaning of bandwidth and quality factor in AC circuits
Application of two-wattmeter method for a 3-phase, 400 V, star-connected system
Given wattmeter readings of 50 kW and 30 kW, calculating:
Circuit power factor
Active and reactive power
Line current
Per-phase impedance
Q5 — Measuring Instruments, Rotating Machines & Applications
Designing a voltmeter by calculating series resistance of a moving-coil instrument
Explaining double-field revolving theory of induction motors
Listing applications of three-phase synchronous motors
This section checks a student’s mastery of electrical machine theory, AC measurements, and advanced power system analysis.