This Engineering Physics question paper is designed to assess a student’s understanding of Relativity, Quantum Mechanics, Electromagnetic Theory, Lasers, Interference, Diffraction, Thin Films, Polarization, and Optical Fiber Communication. The paper is divided into three major sections: A, B, and C, each focusing on different levels of conceptual depth—from basic definitions to advanced derivations and numerical applications.
SECTION A – Short Conceptual Questions (Q1a–Q1g)
Total Marks: 14 (2 marks × 7 questions)
Section A tests foundational knowledge and clarity of basic concepts that form the backbone of engineering physics.
Q1(a)
Is Earth an inertial or non-inertial frame? Justification required.
→ Tests understanding of reference frames and Newton’s laws.
Q1(b)
Wien’s displacement law.
→ Checks understanding of blackbody radiation and temperature–wavelength relation.
Q1(c)
Group velocity.
→ Conceptual understanding of wave packets and energy propagation.
Q1(d)
Dispersive power of a plane transmission grating.
→ Tests optics and diffraction fundamentals.
Q1(e)
Difference between spontaneous and stimulated emission.
→ Core concept for lasers and quantum transitions.
Q1(f)
Specific rotation.
→ Concept used in optical activity and polarimetry.
Q1(g)
Acceptance angle of optical fiber.
→ Key parameter in fiber optics determining light-guiding capability.
This section ensures students are comfortable with definitions, physical meaning, and basic scientific laws.
SECTION B – Descriptive & Derivational Questions (Q2a–Q2e)
Total Marks: 21 (Attempt any 3 × 7 marks)
This section evaluates a student’s analytical ability, derivation skills, and conceptual explanations.
Q2(a) – Galilean Transformation & Invariance
Derive Galilean transformation and prove that length and acceleration remain invariant under these transformations.
Q2(b) – Planck’s Radiation Law
Complete derivation with explanation of why Planck’s law is valid for all wavelengths.
Q2(c) – Plane Transmission Grating
Construction, theory, and spectral formation—important for diffraction and resolving power.
Q2(d) – Ruby Laser & Four-Level Advantage
Compares three-level and four-level lasers; explains ruby laser construction and population inversion.
Q2(e) – Holography
Covers principle, formation of hologram, reconstruction, and uniqueness of holography.
This section targets higher-order thinking and understanding of physical processes.
SECTION C – Long Answer Questions (Q3–Q7)
Each question carries 7 marks; attempt any one part from each.
These questions require deep conceptual understanding, mathematical derivations, and numerical accuracy.
Q3 – Relativity Concepts
Q3(a)
Relativistic velocity addition theorem + consistency with Einstein’s postulate.
→ A major derivation in Special Relativity.
Q3(b)
Time dilation, derivation, and a numerical question to find the speed at which a clock loses 1 minute per hour.
→ Tests real-world application of relativity.
Q4 – Quantum Mechanics
Q4(a)
Davisson–Germer experiment → proof of wave nature of electrons.
→ Fundamental experimental validation of de-Broglie waves.
Q4(b)
Energy states for particle in 1-D box + probability calculation for ground state.
→ Involves quantization and probability distribution.
Q5 – Interference & Diffraction
Q5(a)
Interference due to wedge-shaped thin film → derivation for fringe width.
→ Important for understanding thin film patterns.
Q5(b)
Fraunhofer diffraction at a single slit → derive intensity formula + numerical.
→ Tests ability to interpret diffraction patterns.
Q6 – Polarization & Optical Activity
Q6(a)
Double refraction + calculation of quarter-wave plate thickness for quartz.
→ Focuses on birefringence and phase retardation.
Q6(b)
Optical activity + Fresnel’s theory + derivation of rotation angle.
→ Strong conceptual + mathematical question.
Q7 – Optical Fiber Communication
Q7(a)
Difference between single-mode and multimode fibers, with characteristics.
→ Important for communication engineering.
Q7(b)
Dispersion, attenuation, and calculation of fiber loss in dB/km.
→ Tests numerical and conceptual understanding.
