Examoogle
ExamsTest SeriesCBATRank CheckPrevious Year PapersPassBook StoreMy BooksAI Tutor
ЁЯЫТ0
рдЕA
Examoogle

India's most trusted platform for competitive exam PDF books. Expert-authored, watermark-protected, instant access.

Exams & Practice
All Exams & SyllabusMock Test SeriesPrevious Year PapersPractice Questions (MCQs)Recruitment Notifications
Quick Links
Examoogle AI TutorExam NewsBook StoreMy BooksLogin / Sign Up
Support
About UsRefund PolicyPrivacy PolicyTerms of UseContact Us
┬й 2026 Examoogle. India's #1 competitive exam AI tutor.
ЁЯФТ SSL SecuredЁЯУ▒ UPI AcceptedЁЯз╛ GST Invoice
Examoogle

Join 60,000+ competitive exam aspirants

or with email
By continuing, you agree to ourTerms of Service&Privacy Policy
Your Cart
SubtotalтВ╣0
TotalтВ╣0
Examoogle тАв User тАв info@examoogle.com тАв EE-2024-8821
Chapter 1 of 12 тАв Page 1 of 248ЁЯФТ Protected PDF тАв Watermarked
Back to Practice Questions
ElectricalElectromagnetics Field Theory
PrevNext

Divergence of the electric flux density in free space is

A

111

B

000

C

тИТ1-1тИТ1

D

тИЮ\inftyтИЮ

Correct Answer

тЪЩя╕П TE тАв Technical Concept & PrincipleElectricalElectromagnetics Field Theory
Option B

000

Quick Summary:

According to Gauss's Law in differential form, the divergence of the electric flux density (DтГЧ\vec{D}D) is equal to the volume charge density (╧Бv\rho_v╧БvтАЛ). In free space, there are no charges present, therefore ╧Бv=0\rho_v = 0╧БvтАЛ=0, which results in a divergence of zero.

тЪЩя╕ПTETechnical SolutionConcept & Principle
ЁЯТб Explanation

According to Gauss's Law in differential form, the divergence of the electric flux density (DтГЧ\vec{D}D) is equal to the volume charge density (╧Бv\rho_v╧БvтАЛ). In free space, there are no charges present, therefore ╧Бv=0\rho_v = 0╧БvтАЛ=0, which results in a divergence of zero.

ЁЯФв Key Formulas

тИЗтЛЕDтГЧ=╧Бv\nabla \cdot \vec{D} = \rho_vтИЗтЛЕD=╧БvтАЛ тАФ Differential form of Gauss's Law

тИЗтЛЕDтГЧ=0\nabla \cdot \vec{D} = 0тИЗтЛЕD=0 тАФ Divergence in free space

тЪЩя╕П Working Principle

Maxwell's first equation for electrostatic fields is derived from Gauss's Law, which states that the net electric flux emanating from a closed surface is proportional to the enclosed charge. In free space (vacuum), the net charge density is zero everywhere. Consequently, the divergence operator acting on the electric flux density field must yield a scalar value of zero, indicating the absence of sources or sinks (charges) in the region.

ЁЯУМ Key Points
  • тЦ╕

    Electric flux density DтГЧ\vec{D}D is related to electric field intensity by DтГЧ=╧╡0EтГЧ\vec{D} = \epsilon_0 \vec{E}D=╧╡0тАЛE

  • тЦ╕

    A zero divergence field is often called a solenoidal field

  • тЦ╕

    In free space, ╧Бv=0\rho_v = 0╧БvтАЛ=0 as there are no free charges

тЬЕ Advantages
  • тЦ╕

    Simplifies Maxwell's equations for electromagnetic wave propagation

  • тЦ╕

    Confirms that electric fields in vacuum are continuous

ЁЯЫая╕П Applications / Uses
  • тЦ╕

    Analysis of plane wave propagation in vacuum

  • тЦ╕

    Calculation of field distribution in transmission lines

ЁЯУД Additional Information
  • тЦ╕

    If charges were present, divergence would be non-zero and equal to the local charge density.

  • тЦ╕

    This condition is essential for deriving the Helmholtz wave equation for the electric field.

ЁЯУК Diagram / Illustration
Gauss's Law in Free Space
тИЗтЛЕDтГЧ\nabla \cdot \vec{D}тИЗтЛЕD
╧Бv=0\rho_v = 0╧БvтАЛ=0
тЬЕ

B is correct тАФ The divergence of electric flux density in free space is 0 because there are no free charges to act as sources or sinks for the flux.

Core Concepts Used
Click any tag to open in AI Tutor
Gauss's Law Divergence Operator Electric Flux Density Free Space Permittivity
ЁЯТб EXAM TIP

Remember that the divergence of magnetic flux density (тИЗтЛЕBтГЧ\nabla \cdot \vec{B}тИЗтЛЕB) is always 0 everywhere, not just in free space, due to the non-existence of magnetic monopoles.

Related Questions

ElectricalElectromagnetics Field Theory
For air, the Maxwell's equation hold true is
ElectricalElectromagnetics Field Theory
For any metals, the Maxwell's equation hold true is
ElectricalElectromagnetics Field Theory
MaxwellтАЩs equation not be represented in
ElectricalElectromagnetics Field Theory
Maxwell's equation derived from AmpereтАЩs law is
ElectricalElectromagnetics Field Theory
Maxwell's equation derived from FaradayтАЩs law is

Discussion (0)

Loading discussion...
PrevNext