Code: 104404Electronics & Comm. Eng.4th Semester2 Examination Papers

Electromagnetic Theory

Official Bihar Engineering University examination question papers, marks distribution, and questions transcript. Available exam sessions: 2024, 2023.

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Official Exam Paper TranscriptB.Tech 4th Semester Examination, 2024
Bihar Engineering University, Patna
B.Tech 4th Semester Examination, 2024

Electromagnetic Theory

Time: 03 HoursCode: 104404Full Marks: 70

Instructions:

  1. The marks are indicated in the right-hand margin.
  2. There are NINE questions in this paper.
  3. Attempt FIVE questions in all.
  4. Question No. 1 is compulsory.
Q.1 Choose the correct answer of the following (any seven question only):[14]
  1. The divergence of the vector field is

    1. Vector
    2. Scalar
    3. Can't be both
    4. None
  2. The unit of electric field intensity

    1. Volt
    2. Volt per metre
    3. Tesla
    4. Metre
  3. In Gauss's Law the electric field is related to

    1. The charge density
    2. The potential difference
    3. The charge enclosed
    4. The capacitance
  4. The electric field at a point due to an infinite sheet of charge is:

    1. [σ] / [ε0]
    2. [σ] / [2ε0]
    3. [2ε0] / [σ]
    4. 0
  5. The force on a charged particle moving in a magnetic field is maximum when the angle between the velocity and magnetic field is:

    1. 0°
    2. 45°
    3. 90°
    4. 180°
  6. The energy density in magnetic field is given by

    1. [μH2] / [2]
    2. H2/2μ
    3. 2
    4. None
  7. The dot product of the vectors 3i−2j+5k and −i+3j+2k is,

    1. -1
    2. 1
    3. 0
    4. -3i
  8. The Pointing vector P is

    1. E×H
    2. E·H
    3. 1/2E×H
    4. (E×H)2
  9. The Maxwell's equation ∇·B = 0 is due to

    1. Monopole does not exit
    2. Coulomb's Law
    3. Existence of monopoles
    4. Ampere Circuital Law
  10. Curl of gradient of a vector is

    1. 0
    2. Null Vector
    3. Unity
    4. Depends on the constants of the vector
Q.2 Solve both questions :[7+7=14]
  1. Write the differential elements (dl, da, dv) in both Cartesian, cylindrical co-ordinate system.

  2. State divergence theorem. What will be divergence to position vector?

Q.3 Solve both questions :[7+7=14]
  1. Given the two points, C(−3,2,1) and D(r=5,θ=20°,φ=−70°). find: (i) The spherical coordinates of C (ii) The Cartesian coordinates of D

  2. Find the divergence of A= 3x2ax+ 5x2y2ay+ xyz3az where ax, ay and az are unit vectors in cartesian coordinates at point (1,1,1)

Q.4 Solve both questions :[7+7=14]
  1. State and derive Coulomb's law. Write coulomb's law in vector forms.

  2. Derive an expression for intensity of electric field at a point distant r from a point charge.

Q.5 Solve both questions :[7+7=14]
  1. An infinite long line charge of uniform density ρL C/cm is situated along the z-axis. Obtain electric field intensity due to this charge using Gauss's law.

  2. Derive energy density in electrostatic field.

Q.6 Solve both questions :[7+7=14]
  1. Four 3pC charges are at the corners of a 1-m square. The two charges at the left side of the square are positive. The two charges on the right side are negative. Find the field E at the centre of the square, εr=1

  2. What do you understand by capacitance of a capacitor? Deduce and expression for the capacitance of a parallel plate capacitor. How will it be modified when the gaps between the plates is filled with a dielectric?

Q.7 Solve both questions :[7+7=14]
  1. Show that the Faraday's law of electromagnetic induction can be expressed as ∇×E = −∂B/∂t. Write down its integral form.

  2. Explain the concept of displacement current and show how it led to the modification of the Ampere's law.

Q.8 Solve both questions :[7+7=14]
  1. Discuss reflection of plane electromagnetic wave incident normally on a perfect dielectric and obtain expressions for the two reflection coefficients of electric and magnetic fields.

  2. Define Poynting vector. Mention any two properties of uniform plane wave.

Q.9 Write short notes on any two of the following:-[14]
    • Biot-Savart's Law
    • Magnetic field boundary condition for isotropic medium
    • Skin Effect
    • Spherical capacitance
  • Related Official Syllabus

    Analog Communication

    104404

    Official BEU curriculum units & topics for this examination subject.

    Unit 1.0: Introduction to Communication Systems

    Basic components of communication systems • Types of communication: Analog vs. Digital • Bandwidth requirements and frequency spectrum and Modulation and its necessity

    Unit 2.0: Amplitude Modulation (AM) Systems

    Principles of amplitude modulation • DSB-SC • SSB • And VSB modulation techniques • Generation and detection of AM and DSB • AM waveforms and frequency spectrum • Modulation index and power relations and AM transmitters and receivers

    Unit 3.0: Angle Modulation

    FM and PM • Transmission FM spectra • Carson 's rule • Narrow band • And wide band FM Generation of FM by Direct Methods • Indirect Generation of FM • The Armstrong Method • Direct Methods of Frequency Demodulation • Slope Detector • Foster Seely or Phase Discriminator • Indirect methods of FM Demodulation • FM Detector using PLL • Comparison of FM and PM

    Unit 4.0: Receivers

    Tuned Radio Frequency (TRF) Receiver • Basic Elements of AM Super-heterodyne receiver • RF Amplifiers Characteristics Sensitivity • Selectivity • Image Frequency Rejection • Mixers Tracking and Alignment • Local Oscillator • IF Amplifier • AGC • AM Receiver using Transistors Communication Receiver • FM Receiver

    Unit 5.0: Noise in Communication Systems

    Types of noise: thermal • Shot • And flicker noise • Signal-to-noise ratio (SNR) and its impact on system performance • Noise figure and noise temperature and Noise in AM and FM systems Pre emphasis and de-emphasis

    View Complete 4th Semester Syllabus

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