(SEM IV) THEORY EXAMINATION 2017-18 BASIC ELECTRICAL ENGINEERING

This document presents the complete Basic Electrical Engineering (REE201) Theory Examination Paper for B.Tech (Semester IV), conducted for the academic session 2017–18. The paper carries a total of 70 marks and the duration is 3 hours, designed to assess both conceptual understanding and analytical problem-solving abilities of engineering students.
 

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The exam is structured into three comprehensive sections—A, B, and C, each targeting different cognitive levels ranging from foundational definitions to complex numerical derivations and machine-based concepts.

Section A – Fundamental Concepts (14 Marks)

Section A contains seven short-answer questions, each testing the student’s grasp of core electrical engineering principles. Topics include:

Definitions of active and passive elements, essential for understanding circuit behavior.

Distinction between unilateral and bilateral elements, significant in network analysis.

Basic electrical quantities such as amplitude, mechanical degrees, and angular velocity.

AC waveform parameters like form factor and peak factor.

Comparison of star and delta configurations, fundamental in 3-phase systems.

Understanding of what information a loop provides in circuit theory.

Concept of speed regulation in electrical machines, crucial for motor performance evaluation.

These questions ensure students have a strong theoretical foundation before moving to advanced applications.

Section B – Applied & Numerical Questions (21 Marks)

This section includes three out of five descriptive and numerical questions, encouraging analytical thinking. Key themes include:

Nodal Analysis for determining current through an 8 Ω resistor.

Application of Norton’s Theorem to analyze circuits efficiently.

Computation of line current, power factor, power, and VA rating for a balanced star-connected 3-phase load.

Transformer design problem involving flux density, turns calculation, and voltage ratio in a core-type transformer.

Determination of slip and number of poles in an induction motor coupled with an alternator system.

These problems test a student's ability to apply theoretical concepts to real-world electrical systems.
 

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Section C – Advanced Derivations & Machine Theory (35 Marks)

This section contains one question from each part, focusing on derivations and detailed explanations:

Part 1 – AC Waveforms

Derivation of rms value, average value, form factor, and analysis of a sinusoidal alternating current.

Interpretation of the equation i = 42.42 sin 628t, including calculation of maximum value and frequency.

Part 2 – RLC Circuits & Resonance

Derivation of impedance, current, and power factor for a series R–L–C circuit, along with vector diagrams.

Detailed explanation of parallel resonance, including salient characteristics important for high-frequency applications.

Part 3 – 3-Phase Circuits & Instruments

Relationship between line and phase currents in a delta-connected load.

Working principle and torque derivation of moving iron type instruments, widely used in measurement systems.

Part 4 – Inductance & Transformers

Definitions and differences between self-inductance, mutual inductance, and associated losses such as hysteresis and eddy current losses.

Principle of operation and EMF equation for a single-phase transformer, a foundational topic in power systems.

Part 5 – AC Machines – Synchronous & Induction Motors

Operation of 3-phase synchronous motors, including their excitation and torque production.

Two-revolving-field theory of single-phase induction motors and methods of starting these machines.

This section ensures students can derive, interpret, and apply advanced formulas and machine theories relevant to the electrical engineering domain.