MAKAUT BS-PH101 Engineering Physics-I Question Bank: Complete Solved Guide for Semesters

Preparing for Maulana Abul Kalam Azad University of Technology (MAKAUT) semester examinations can be challenging, especially for freshman engineering students tackling BS-PH101 (Engineering Physics-I). With a syllabus spanning Optics, Electromagnetism, Quantum Mechanics, Semiconductors, and Crystallography, students often get overwhelmed trying to cover everything.

To help you secure an O-Grade, we have compiled the ultimate MAKAUT Engineering Physics Question Bank with solved textbook problems, step-by-step mathematical derivations, and prior year exam questions (PYQs).

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1. Syllabus Structure and Question Bank Overview

Under the latest MAKAUT curriculum regulations, the BS-PH101 paper carries 100 marks in total, split into 30 marks for Continuous Assessment (CA) internals and 70 marks for the End-Semester Examination.

Here is how the subject units and marking distributions map out across the syllabus:

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2. Unit-Wise Key Conceptual Questions

Below are some of the most critical questions from the Physics Question Bank categorized by their respective units.

Unit I: Wave Optics

• Short Questions (2 Marks):
• *Define Interference.* Explain the difference between constructive and destructive interference.
• *Define Diffraction.* Differentiate between Fresnel and Fraunhofer diffraction.
• Long Questions (5–7 Marks):
• *Describe the Fraunhofer Diffraction due to N-Slits.* Show how the intensity distribution is formed.
• *Explain polarization by reflection with a neat sketch.* Derive Brewster's Law.
• *Nicol Prism*: Explain the construction and working of a Nicol Prism for producing plane-polarized light.

Unit II: Electromagnetism & Dielectrics

• Short Questions (2 Marks):
• *Define dielectric polarization and susceptibility.*
• *What is a Bohr Magneton?* Write down its value and formula.
• *Define Hysteresis.* Sketch the B-H curve and label retentivity and coercivity.
• Long Questions (5–6 Marks):
• Show that P = \epsilon_0(\epsilon_r - 1)E under standard notations.
• Differentiate between polar and non-polar dielectric molecules with examples.

Unit III: Quantum Mechanics & Free Electron Theory

• Short Questions (2–3 Marks):
• *Define mean free path and drift velocity.*
• *Explain the physical significance of the wave function (\psi).* Why must it be normalized?
• Long Questions (6–7 Marks):
• *Derive Schrödinger's Time-Independent Wave Equation*: Start from the classical wave equation and substitute the de Broglie wavelength.
• *Derive Schrödinger's Time-Dependent Wave Equation.*

Unit IV: Semiconductors

• Short Questions (2–3 Marks):
• *What are the applications of the Hall Effect?* (Determining carrier concentration, sign of charge carriers, and mobility).
• *Fermi Energy Level*: Explain the significance of the Fermi level in semiconductors.
• Long Questions (6–7 Marks):
• *Prove that the Fermi level lies exactly in the middle of the forbidden energy gap* for an intrinsic semiconductor at T = 0 K.
• *Conductivity*: Derive the expression for the electrical conductivity of an intrinsic semiconductor (\%sigma = n_i e (\%mu_e + \%mu_h)).

Unit V: Crystallography & X-Ray Diffraction

• Short Questions (2–3 Marks):
• What are Miller indices? How do you calculate them?
• State Bragg's Law of X-ray diffraction.
• Long Questions (5–7 Marks):
• *Describe the Powder X-Ray Diffraction method* with a clean block diagram. Detail its advantages over single-crystal methods.

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3. Step-by-Step Solved Numericals

Let's walk through two typical numerical problems that are highly repeated in MAKAUT engineering physics examinations:

Problem 1: Grating Wavelength Calculation

> Question: *A plane transmission grating having 4,250 lines per cm is illuminated with light normally. In the second-order spectrum, the spectral lines are deviated by 30^\circ. What is the wavelength of the spectral line?*

Solution:

1. Identify the Given Parameters:
2. Number of lines per cm, N = 4250 lines/cm = 425000 lines/m
3. Grating element, d = 1N = 1425000 m \approx 2.353 × 10^{-6} m
4. Order of spectrum, n = 2
5. Angle of deviation, \theta = 30^\circ
6. Apply the Grating Equation:

1. Solve for Wavelength ($\lambda$):

1. Answer: The wavelength of the spectral line is $588.25\text{ nm}$ (or $5882.5\text{ \AA}$).

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Problem 2: Intrinsic Semiconductor Conductivity

> Question: *The following data are given for intrinsic Germanium (Ge) at 300 K. Calculate the electrical conductivity of the sample. Given: n_i = 2.4 × 10^{19} m^{-3}, \mu_e = 0.39 m^2V^{-1}s^{-1}, \mu_h = 0.19 m^2V^{-1}s^{-1}.*

Solution:

1. Identify the Given Parameters:
2. Intrinsic carrier concentration, n_i = 2.4 × 10^{19} m^{-3}
3. Electron mobility, \mu_e = 0.39 m^2V^{-1}s^{-1}
4. Hole mobility, \mu_h = 0.19 m^2V^{-1}s^{-1}
5. Electronic charge, e = 1.6 × 10^{-19} C
6. Apply the Conductivity Formula:

1. Substitute the Values:

1. Answer: The electrical conductivity of the Germanium sample at 300 K is $2.23 \text{ } \Omega^{-1}\text{m}^{-1}$.

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4. Exam Day Derivation Strategy

To maximize scores on long derivation questions, follow these layout rules:

• Start with a Diagram: Always sketch the physical layout (e.g., boundaries of a 1D potential box or thin-film wedge angles) using clear annotations.
• State Assumptions Clearly: Explicitly write down boundary conditions or physical assumptions (e.g., "Assume the potential V(x) = 0 inside the box and V(x) = \infty outside").
• Sequence the Equations: Draw an equation index number, e.g., (Eq. 1), (Eq. 2), so you can reference them in subsequent steps.
• Highlight Final Formulas: Wrap your final derivation in a box so the examiner can locate it immediately.

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Conclusion

Succeeding in MAKAUT's BS-PH101 Engineering Physics course is not about memorizing entire textbooks; it is about mastering the core derivations and solving numerical problems. By focusing on Wave Optics equations, Schrödinger's wave mechanics, and semiconductor Fermi level mathematics, you can easily secure an O-Grade.

Keep practicing these derivations on paper and double-check your mathematical calculations to avoid minor errors!