(SEM I) THEORY EXAMINATION 2020-21 ENGINEERING PHYSICS

This document contains the official AKTU B.Tech 1st Semester 2020–21 Theory Examination question paper for Engineering Physics (KAS101T). It is a full 100-mark, 3-hour examination paper that follows the complete AKTU pattern with Section A, Section B, and Section C. This paper is extremely useful for students preparing for semester exams, sessionals, and internal assessments.

Engineering Physics is a core subject that develops a strong foundation in relativity, electromagnetic theory, quantum mechanics, wave optics, lasers, fibre optics, and matter waves. This official question paper helps students understand the exact exam format, marking scheme, and types of numerical and theoretical questions asked by AKTU.

Detailed Breakdown of the Question Paper

SECTION A – 10 Short Questions (10 × 2 = 20 Marks)

This section includes 10 very short questions, each worth 2 marks, covering fundamental concepts such as:

Einstein’s postulates of Special Relativity

Photon momentum calculation

Displacement current

Why magnetic monopoles do not exist

Wien’s displacement law & Rayleigh-Jeans law

Nature of matter waves

Why independent sources do not show interference

Rayleigh criterion & resolving power

Spontaneous vs stimulated emission

Components of an optical fibre (with diagram)

These questions are ideal for quick revision and fast scoring.

SECTION B – 3 Medium-Length Questions (3 × 10 = 30 Marks)

Students must attempt any 3 out of 5 questions. Topics include:

Lorentz transformations & invariance of space-time interval

Conduction current density & displacement current density calculations

Lowest energy states in an infinite potential well

Thin film interference (soap bubble)

Optical fibre attenuation and power calculation

This section involves numerical problems and conceptual derivations, helping students practice mid-level difficulty questions.

SECTION C – 5 Long Answer Questions (5 × 10 = 50 Marks)

Each question has two alternatives; students must attempt one part from each. These include:

Question 3 – Relativity

Time dilation with derivation & experimental evidence
OR

Mass–energy relation and relativistic kinetic energy

Question 4 – Electromagnetic Theory

Maxwell’s equations in free space + EM wave propagation
OR

Poynting theorem with derivation & significance

Question 5 – Quantum Mechanics

Wave function and derivation of time-independent Schrödinger equation
OR

Compton effect + formula for Compton shift

Question 6 – Wave Optics

Newton’s rings formation + proof for diameters of dark rings
OR

Diffraction due to plane grating

Question 7 – Lasers & Fibre Optics

Construction, working & applications of He-Ne laser
OR

Acceptance angle & numerical aperture derivations

This section prepares students for high-scoring theoretical answers.

Why This Question Paper is Important for Students

This question paper is valuable because it:

Matches the actual AKTU exam pattern

Covers all high-weightage chapters from the syllabus

Includes numerical, derivation-based, and diagram-based questions

Helps build conceptual clarity in core physics topics

Acts as a perfect last-moment revision tool

Shows commonly repeated question formats

Improves confidence for both theory and problem-solving

It is especially helpful for students of CSE, IT, ECE, EE, ME, CE, EI, EN and all first-year engineering programs.