BSc CSIT Physics (PHY118) Complete Guide: TU 1st Semester Syllabus, Concepts, Derivations & Exam Preparation

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Introduction

Physics (PHY118) is one of the most misunderstood courses in the BSc CSIT first-semester curriculum. Many students assume it will be a repeat of high school physics — mechanics, simple circuits, basic optics — and are caught off guard when the actual syllabus jumps into rotational dynamics, electromagnetic fields, atomic theory, quantum mechanics, solid-state physics, and the physics behind semiconductor devices and integrated circuits. This isn't a generic physics survey course; it's specifically designed to give computer science students the physical foundation behind the hardware their entire field depends on.

That connection is worth taking seriously. The reason your CPU can switch billions of times per second comes down to semiconductor band theory (Unit 5) and transistor physics (Unit 6). The reason logic gates work the way they do, and how millions of them get packed onto a single chip, is the subject of Unit 7. Even quantum mechanics (Units 3 and 4) isn't just academic — it's the foundation of quantum computing, an area increasingly relevant to computer science graduates. Students who treat PHY118 as a checkbox course often struggle later when Computer Organization, Digital Logic, or advanced electives assume this physical intuition is already in place.

This guide walks through the official PHY118 syllabus unit by unit, explains the physics with real hardware-relevant examples rather than abstract definitions, includes the formulas and selected derivations you'll need, and lays out a study plan for exam preparation. Detailed unit-wise articles with full derivations and solved numericals are linked at the end.

Official Course Information

Particular	Details
Course Title	Physics
Course Code	PHY118
Semester	First Semester
Nature of Course	Theory + Lab
Full Marks	60 + 20 + 20
Pass Marks	24 + 8 + 8
Credit Hours	3

Course Description

PHY118 covers oscillatory motion and rotational dynamics, electric and magnetic field theory, the fundamentals of atomic theory and quantum mechanics, solid-state physics including band theory, semiconductors and semiconductor devices, universal logic gates, and the physics of manufacturing integrated circuits.

Course Objective

The course aims to provide students with a working knowledge of physics that can be directly applied to computer science and information technology — particularly the physical principles behind modern electronics, semiconductor devices, and digital logic hardware.

Why PHY118 Matters Beyond the Exam

It's easy to see physics as disconnected from "real" computer science, but PHY118 is arguably the most hardware-relevant course in the first-year curriculum. Band theory and semiconductor physics (Units 5–6) explain why silicon, rather than any other material, became the basis of the entire chip industry. Universal gates and IC physics (Unit 7) is the physical layer underneath the Digital Logic course most CSIT students take around the same time. Quantum mechanics (Units 3–4) is foundational not just out of academic tradition, but because quantum computing — a real and growing subfield — depends on the exact concepts covered here: superposition, the uncertainty principle, and wave functions.

Official Unit-Wise Syllabus Overview

Unit 1: Rotational Dynamics and Oscillatory Motion (5 Hrs)

This unit covers moment of inertia and torque, rotational kinetic energy, conservation of angular momentum, and spring oscillation — including frequency, period, amplitude, phase angle, and energy. Rotational dynamics shows up more in computing hardware than students expect: the read/write mechanism in older hard disk drives depends on precise rotational dynamics, and gyroscope sensors in smartphones use rotational principles to detect orientation. Oscillatory motion (Simple Harmonic Motion) is the conceptual basis for understanding any periodic signal, including the electrical oscillations used in clock circuits later in Unit 7.

Unit 2: Electric and Magnetic Field (5 Hrs)

This unit covers electric and magnetic fields and potential, the force on a current-carrying wire, magnetic dipole moment, the force on a moving charge, the Hall effect, and electromagnetic waves. The Hall effect is a particularly direct hardware connection: Hall effect sensors are used in smartphones to detect when a case or flip-cover is closed, and in brushless motors to detect rotor position. Electromagnetic wave theory from this unit also underlies how Wi-Fi and Bluetooth radios transmit data wirelessly.

Unit 3: Fundamentals of Atomic Theory (8 Hrs)

This is one of the two heaviest units in the course, covering blackbody radiation, the Bohr model of the atom, the hydrogen spectrum, the Franck-Hertz experiment, de Broglie's hypothesis, the uncertainty principle, matter waves, and group velocity. This unit explains why electrons in atoms only occupy specific discrete energy levels rather than any arbitrary energy — a concept that directly explains LED light emission (electrons dropping between specific energy levels emit photons of a specific color) and is the conceptual entry point into the band theory covered later in Unit 5.

Unit 4: Methods of Quantum Mechanics (5 Hrs)

This unit covers Schrödinger's theory of quantum mechanics, an outline of solving the Schrödinger equation for the hydrogen atom, space quantization and electron spin, and atomic wave functions. This is the most mathematically demanding unit in the course, since it moves from the semi-classical Bohr model into the full quantum-mechanical description of the atom. The payoff is that this framework — wave functions and quantized states — is exactly what quantum computing's qubits are built on.

Unit 5: Fundamentals of Solid State Physics (6 Hrs)

This unit covers crystal structure and bonding, the classical and quantum mechanical free electron models, Bloch's theorem, the Kronig-Penney model, the tight-binding approximation, and how these models explain the difference between conductors, insulators, and semiconductors, along with effective mass and "holes." This is the unit that directly answers the question every CS student should eventually ask: why is silicon used to build computer chips? The answer lies in band theory — the arrangement of allowed and forbidden electron energy bands that this unit develops mathematically.

Unit 6: Semiconductor and Semiconductor Devices (8 Hrs)

Tied for the heaviest unit in the course, this covers intrinsic and extrinsic semiconductors, the electrical conductivity of semiconductors, photoconductivity, metal-metal junctions and contact potential, the semiconductor diode, the Bipolar Junction Transistor (BJT), and the Field Effect Transistor (FET). This unit is the physics behind the transistor — the single device that, multiplied by billions, makes up every modern CPU. Understanding how a p-n junction creates a diode, and how that extends into a transistor that can switch or amplify signals, is the physical foundation of every digital circuit you'll study in later courses.

Unit 7: Universal Gates and Physics of Integrated Circuits (8 Hrs)

The final unit, also carrying the most teaching hours, covers universal logic gates, RTL and TTL gate families, memory and clock circuits, and the physical process of manufacturing integrated circuits — semiconductor purification (zone refining), single crystal growth, and fabricating electronic components onto a chip. This unit is where the physics, electronics, and digital logic strands of the course converge: it explains both how logic gates are physically realized in silicon and how an actual CPU chip is manufactured from raw material to finished product.

Quick Comparison Tables

Conductor vs. Insulator vs. Semiconductor

Aspect	Conductor	Insulator	Semiconductor
Band Gap	No gap (overlapping bands)	Large band gap	Small/moderate band gap
Conductivity	High	Very low	Between conductor and insulator
Effect of Temperature	Conductivity decreases slightly	Conductivity stays very low	Conductivity increases
Example	Copper, aluminum	Rubber, glass	Silicon, germanium

Intrinsic vs. Extrinsic Semiconductor

Aspect	Intrinsic	Extrinsic
Purity	Pure semiconductor, no doping	Doped with impurity atoms
Charge Carriers	Equal electrons and holes	Majority/minority carriers depend on dopant type
Conductivity	Lower, purely temperature-dependent	Higher, controllable via doping level
Example	Pure silicon	Silicon doped with phosphorus (n-type) or boron (p-type)

BJT vs. FET

Aspect	BJT	FET
Control Mechanism	Controlled by base current	Controlled by gate voltage
Input Impedance	Relatively low	Very high
Power Consumption	Generally higher	Generally lower
Common Use	Amplification, switching	Modern digital logic circuits (e.g., MOSFETs in CPUs)

RTL vs. TTL Logic Families

Aspect	RTL	TTL
Core Components	Resistors and transistors	Transistors only (no resistor-based input stage)
Switching Speed	Slower	Faster
Noise Immunity	Lower	Higher
Historical Role	One of the earliest logic families	Dominant logic family for decades before CMOS

Formula Quick-Reference

Topic	Key Formula
Torque	τ = r × F = rF sinθ, and τ = Iα
Moment of inertia	I = Σmr² (discrete) or ∫r² dm (continuous)
Rotational kinetic energy	KE = ½Iω²
Angular momentum	L = Iω (conserved when net external torque = 0)
SHM displacement	x(t) = A sin(ωt + φ)
SHM angular frequency (spring)	ω = √(k/m), T = 2π√(m/k)
Energy in SHM	E = ½kA²
Coulomb's Law / Electric field	F = kq₁q₂/r², E = F/q
Force on current-carrying wire	F = BIL sinθ
Magnetic dipole moment	μ = IA
Force on a moving charge (Lorentz force)	F = qvB sinθ
Hall voltage	V_H = IB / (nqt), where n = carrier density, t = thickness
Planck's relation (blackbody/photon energy)	E = hf
Bohr model energy levels	Eₙ = −13.6 eV / n²
Bohr radius	rₙ = n²a₀
de Broglie wavelength	λ = h/p = h/(mv)
Heisenberg uncertainty principle	Δx · Δp ≥ ℏ/2
Time-independent Schrödinger equation	−(ℏ²/2m)(d²ψ/dx²) + Vψ = Eψ
Semiconductor conductivity	σ = e(nμₙ + pμₚ)
Diode current equation	I = I₀(e^(qV/kT) − 1)

Selected Derivations

These are illustrative derivations — the kind most likely to appear as "derive" questions — not a full replacement for working through the textbook derivations yourself.

SHM equation from Hooke's Law: Starting from Hooke's Law, the restoring force on a mass on a spring is F = −kx. By Newton's second law, F = ma = m(d²x/dt²), so m(d²x/dt²) = −kx, giving d²x/dt² = −(k/m)x. This is the standard differential equation for simple harmonic motion, whose general solution is x(t) = A sin(ωt + φ), where ω = √(k/m) — directly connecting the spring constant and mass to the oscillation frequency.

Bohr model energy levels (sketch): Bohr's model assumes the electron orbits the nucleus in circular orbits where angular momentum is quantized: mvr = nℏ. Combining this quantization condition with the requirement that the Coulomb attraction provides the centripetal force (kZe²/r² = mv²/r) lets you solve for the allowed orbit radii rₙ and, substituting back into the total energy expression (kinetic plus potential), arrive at the quantized energy levels Eₙ = −13.6 eV/n² for hydrogen.

Hall voltage: When a current-carrying conductor sits in a magnetic field perpendicular to the current, moving charge carriers experience a sideways force (qvB) that pushes them to one side of the conductor, creating a transverse electric field. At equilibrium, this electric field's force on the carriers balances the magnetic force, qE = qvB, giving E = vB. Since the Hall voltage is V_H = Ed (across thickness d) and current I = nqvA (with A = cross-sectional area), substituting and simplifying yields V_H = IB/(nqt), where t is the thickness in the direction of the field.

How PHY118 Is Typically Tested

With marks split as 60 (theory) + 20 (lab/practical) + 20 (internal), the theory exam generally combines short conceptual questions, derivation-based long questions, and numerical problems. Given that Units 3, 6, and 7 carry the most teaching hours (8 hours each), they tend to be weighted more heavily, and Unit 6 and 7 in particular are common sources of long-answer questions since they combine derivation, conceptual explanation, and real device behavior. The lab component requires performing at least one experiment from Units 1, 2, and from the 5–6–7 group, so practical familiarity with circuit-building and measurement (not just theory) matters for the lab marks.

Study Plan

30-Day Plan

• Days 1–5: Unit 1 (Rotational Dynamics and Oscillatory Motion)
• Days 6–10: Unit 2 (Electric and Magnetic Field)
• Days 11–17: Unit 3 (Fundamentals of Atomic Theory) — the heaviest, most conceptually dense unit
• Days 18–22: Unit 4 (Methods of Quantum Mechanics)
• Days 23–26: Unit 5 (Solid State Physics)
• Days 27–29: Units 6–7 (Semiconductors, Universal Gates and IC Physics)
• Day 30: Full formula sheet and derivation review

15-Day Plan

• Days 1–2: Unit 1
• Days 3–4: Unit 2
• Days 5–7: Unit 3
• Days 8–9: Unit 4
• Days 10–11: Unit 5
• Days 12–14: Units 6–7
• Day 15: Formula sheet and derivation review

7-Day Plan

• Day 1: Units 1–2
• Day 2–3: Unit 3 (don't compress this one further — it's heavily tested)
• Day 4: Unit 4
• Day 5: Unit 5
• Day 6: Units 6–7
• Day 7: Formula sheet, derivations, and past-question practice

Night-Before Exam Strategy

• Review the formula quick-reference table rather than rereading full explanations.
• Re-derive the SHM equation, Bohr energy levels, and Hall voltage formula once each to keep the derivation steps fresh.
• Skim the comparison tables (conductor/insulator/semiconductor, BJT vs FET) since "differentiate between" questions are common and quick to lose marks on if details are mixed up.
• Don't attempt new numerical problem types this late — focus on formats you've already practiced.

Common Mistakes Students Make in PHY118

• Treating this as basic physics and underestimating how conceptually dense Units 3 and 4 (atomic theory and quantum mechanics) actually are.
• Memorizing final formulas without understanding the derivation steps, which costs marks on "derive" questions even when the final answer is recalled correctly.
• Confusing BJT and FET operating principles, or mixing up intrinsic and extrinsic semiconductor properties.
• Skipping the lab component's hands-on circuit work in favor of only studying theory.
• Not connecting Unit 7 (Universal Gates and IC Physics) to the Digital Logic course, missing an opportunity to reinforce both subjects together.
• Under-preparing numerical problems, especially Hall effect and Bohr model energy-level calculations, which are common exam favorites.

Tips to Score High Marks

• Practice derivations by writing them out from memory, not just reading them, since derivation questions test recall of the logical steps, not just the final formula.
• Connect each unit to a real device — Hall sensors, LEDs, diodes, transistors, logic gates — since concrete examples make abstract quantum and solid-state concepts far easier to retain under exam pressure.
• Keep a single formula sheet (like the one in this guide) and revise it daily during the final two weeks.
• Work through Hall effect and Bohr model numericals repeatedly, since they reappear in slightly different forms across past papers.
• Don't neglect Units 6 and 7 in favor of the more "classical-feeling" early units — they carry the most teaching hours and the most direct relevance to your CS coursework.

Frequently Asked Questions (FAQs)

Is PHY118 the same as the physics taught in +2 / high school? No. While Unit 1 and 2 build on familiar mechanics and electromagnetism concepts, Units 3 through 7 move into atomic theory, quantum mechanics, solid-state physics, and semiconductor device physics, which go well beyond a typical high school physics curriculum.

Which units carry the most weight in the PHY118 exam? Units 3, 6, and 7 each carry 8 teaching hours, the most of any units in the course, and tend to be represented proportionally in the exam.

Is PHY118 relevant to computer science, or just a general requirement? It's directly relevant — semiconductor and solid-state physics (Units 5–6) explain why silicon-based chips work the way they do, and Unit 7 connects directly to the physical realization of logic gates covered in the Digital Logic course.

How should I prepare if I only have a week before the exam? Prioritize Unit 3 (Atomic Theory) and Units 6–7 (Semiconductors and IC Physics) since they carry the most teaching hours, then use the formula quick-reference and comparison tables in this guide for fast review of the remaining units.

Do I need to memorize full derivations, or just the final formulas? Understanding derivations is important since TU exams commonly include "derive" questions, and recalling the logical steps also makes the final formulas easier to remember correctly under exam pressure.

What's the difference between the Bohr model and the full quantum mechanical model in Unit 4? The Bohr model (Unit 3) is a semi-classical model that assumes quantized circular orbits to explain atomic spectra, while the quantum mechanical model (Unit 4) uses the Schrödinger equation to describe the electron as a wave function, providing a more complete and accurate description, including orbital shapes and electron spin.

Why does this course cover IC manufacturing physics? Because BSc CSIT graduates are expected to understand not just how to program computers but the physical hardware layer beneath them — knowing how a chip is actually fabricated provides context for limitations like Moore's Law and the physical challenges of further miniaturization.

Is the lab component difficult? The lab requires performing at least one experiment from Units 1, 2, and from the 5–6–7 group, generally involving practical measurement and circuit work rather than purely theoretical problems, so hands-on practice beforehand helps significantly.

Conclusion

PHY118 covers far more ground than its "Physics" title suggests, moving from classical rotational dynamics through quantum mechanics into the solid-state and semiconductor physics that quite literally explains how your computer works. Use the formula reference and derivations above as quick-recall tools, but build real understanding around the hardware connections — Hall sensors, LEDs, transistors, and IC fabrication — since those are what make this course feel relevant rather than abstract.

For full chapter-wise notes, complete derivations, and solved numericals for each topic, see the detailed unit-wise guides:

• Unit 1: Rotational Dynamics and Oscillatory Motion (coming soon)
• Unit 2: Electric and Magnetic Field (coming soon)
• Unit 3: Fundamentals of Atomic Theory (coming soon)
• Unit 4: Methods of Quantum Mechanics (coming soon)
• Unit 5: Fundamentals of Solid State Physics (coming soon)
• Unit 6: Semiconductor and Semiconductor Devices (coming soon)
• Unit 7: Universal Gates and Physics of Integrated Circuits (coming soon)

You may also find these related guides useful: BSc CSIT Mathematics-I (MTH117) Complete Guide, Introduction to Information Technology (CSC114) Complete Guide, and Digital Logic Notes.