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The maxwells four equations are written ...

The maxwells four equations are written as
(`i`) `ointvecE.vec(dS)=(q_(0))/(epsilon_(0))`
(`ii`) `ointvecB.vec(dS)=0`
(`iii`) `ointvecE.vec(dl)=(d)/(dt)ointvecB.vec(dS)`
(`iv`) `ointvecB.vec(dl)=mu_(0)epsilon_(0)(d)/(dt)ointvecE.vec(dS)`
The equations which have sources of `vecE` and `vecB` are

A

(`i`), (`ii`), (`iii`)

B

(`i`), (`ii`)

C

(`i`) and (`iii`) only

D

(`i`) and (`iv`) only

Text Solution

AI Generated Solution

The correct Answer is:
To determine which of Maxwell's equations have sources of the electric field \(\vec{E}\) and the magnetic field \(\vec{B}\), we will analyze each equation step by step. ### Step 1: Analyze Equation (i) The first equation is given by: \[ \oint \vec{E} \cdot d\vec{S} = \frac{q_0}{\epsilon_0} \] This equation is Gauss's law for electricity. It states that the electric flux through a closed surface is proportional to the charge enclosed within that surface. Thus, this equation has a source for the electric field \(\vec{E}\) (the charge \(q_0\)). ### Step 2: Analyze Equation (ii) The second equation is: \[ \oint \vec{B} \cdot d\vec{S} = 0 \] This equation indicates that the magnetic flux through a closed surface is zero, implying that there are no magnetic monopoles (sources) in classical electromagnetism. Therefore, this equation does not have a source for the magnetic field \(\vec{B}\). ### Step 3: Analyze Equation (iii) The third equation is: \[ \oint \vec{E} \cdot d\vec{l} = \frac{d}{dt} \oint \vec{B} \cdot d\vec{S} \] This is Faraday's law of induction, which relates the electric field around a closed loop to the rate of change of magnetic flux through the loop. While it describes how an electric field can be induced by a changing magnetic field, it does not have a source for the electric field \(\vec{E}\). ### Step 4: Analyze Equation (iv) The fourth equation is: \[ \oint \vec{B} \cdot d\vec{l} = \mu_0 \epsilon_0 \frac{d}{dt} \oint \vec{E} \cdot d\vec{S} \] This is Ampère-Maxwell law, which states that the line integral of the magnetic field around a closed loop is related to the rate of change of electric flux through the loop and the current. However, it does not have a source for the magnetic field \(\vec{B}\) in the classical sense. ### Conclusion From the analysis: - Equation (i) has a source for \(\vec{E}\) (the charge \(q_0\)). - Equation (ii) does not have a source for \(\vec{B}\). - Equation (iii) does not have a source for \(\vec{E}\). - Equation (iv) does not have a source for \(\vec{B}\). Thus, the equations which have sources are: - **(i)** for \(\vec{E}\). ### Final Answer The equation which has a source of \(\vec{E}\) is (i). There are no equations with sources for \(\vec{B}\). ---
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The four Maxwell's equations and the Lorentz force law (which together constitution the fundations of all the classical electromagnetism) are listed below: (i) oint vecB.vec(ds)=q//(in_0) (ii) oint vecB.vec(ds)=0 (iii) oint vecE.vec(dl)=-d/(dt) int_svecB.vec(ds) (iv) oint vecB.vec(dl)=mu_0I+mu_0d/(dt)int_s vecb.vec(ds) Lorentz force law: vecF=q(vecE+vecvxxvecB) Answer the following question regarding these equation: (a) Give the name (s) associated with some of the four equation above. (b) Which equations above contain source vecE and vecB and which do not? what do the equations reduce to in a source-free region? (c) Write down Maxwell's equations for steady (i.e. time independent) electric and magnetic fields. (d) If magnetic monopoles existed, which of the equations would be modified? Suggest how they might be modified? (e) Which of the four equations shown that magnetic field lines cannot start from a point nor end at a point? (f) Which of the four equations show that electrostatic field lines cannot form closed loops? (g) The equations listed above refer to integrals of vecE and vecB over loops/surfaces Can we write down equations for vecE and vecB for each point in space? (h) Are the equations listed above true for different types of media: dielectrics, conductors, plasmas etc.? (i) Are the equation true fora arbitrarily high and low values of vecE,vecB,q,I ?

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Knowledge Check

  • The maxwells four equations are written as i. oint vec(E).vec(dS) = (q)/(epsilon_(0)) ii. oint vec(B).vec(dS) = 0 iii. oint vec(E ).vec(dl) = (d)/(dt) oint vec(B).vec(dS) iv. oint vec(B).vec(dl) = mu_(0) epsilon (d)/(dt) oint vec(E).vec(dS) The equations which have sources of vec(E ) and vec(B) are

    A
    (i), (ii),(iii)
    B
    (i), (ii)
    C
    (i) and (iii) only
    D
    (i) and (iv) only
  • The maxwell’s equation : oint vec(B).vec(dl) = mu_(0) (i+varepsilon_(0).(dphi_(E))/dt) is a statement of -

    A
    Faraday’s law of induction
    B
    Modified Ampere’s law
    C
    Gauss’s law of electricity
    D
    Gauss’s law of magnetism
  • Maxwell's equation oint vecB * d vecs = 0 says

    A
    Monopole can exist
    B
    Only dipole can exist
    C
    Magnetic field lines are closed loop
    D
    Net flux through surface is zero
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