
The problem asks to match the laws of electromagnetism (List-I) with their corresponding equations (List-II). These laws are derived from Maxwell’s equations.
Gauss’s Law of Electrostatics states that the total electric flux through a closed surface is equal to the charge enclosed divided by the permittivity of free space. The corresponding equation is:
\[ \oint \mathbf{E} \cdot d\mathbf{a} = \frac{1}{\epsilon_0} \int \rho dV. \]
This matches D – I.
Faraday’s Law of Electromagnetic Induction states that the electromotive force induced in a closed loop is equal to the negative rate of change of the magnetic flux through the loop. The corresponding equation is:
\[ \oint \mathbf{E} \cdot d\mathbf{l} = - \frac{d}{dt} \int \mathbf{B} \cdot d\mathbf{a}. \]
This matches B – III.
Ampere’s Law (with Maxwell’s correction) relates the line integral of the magnetic field around a closed loop to the current passing through the loop and the displacement current. For steady currents, the corresponding equation is:
\[ \oint \mathbf{B} \cdot d\mathbf{l} = \mu_0 I. \]
This matches C – IV.
Gauss’s Law for Magnetostatics states that the net magnetic flux through a closed surface is zero, indicating there are no magnetic monopoles. The corresponding equation is:
\[ \oint \mathbf{B} \cdot d\mathbf{a} = 0. \]
This matches A – II.
Final Matching:
A – II, B – III, C – IV, D – I
This problem requires matching fundamental laws of electromagnetism (List-I) with their corresponding mathematical integral forms (List-II). We will analyze each law and its mathematical representation to find the correct pairs.
The four laws listed are part of Maxwell's equations, which form the foundation of classical electromagnetism.
We will now match each law from List-I with its corresponding mathematical expression from List-II based on the concepts above.
Step 1: Match 'A. Gauss's law of magnetostatics'
As per the concept, Gauss's law for magnetism states that the net magnetic flux through a closed surface is zero. This corresponds to the mathematical expression:
\[ \oint \vec{B} \cdot d\vec{a} = 0 \]
This expression is listed as II in List-II. Therefore, A matches with II.
Step 2: Match 'B. Faraday's law of electromagnetic induction'
Faraday's law relates the induced EMF (line integral of \( \vec{E} \)) to the rate of change of magnetic flux (time derivative of the surface integral of \( \vec{B} \)). The equation is:
\[ \oint \vec{E} \cdot d\vec{l} = -\frac{d}{dt} \int \vec{B} \cdot d\vec{a} \]
This expression is listed as III in List-II. Therefore, B matches with III.
Step 3: Match 'C. Ampere's law'
Ampere's law relates the line integral of the magnetic field around a closed loop to the enclosed current. The equation is:
\[ \oint \vec{B} \cdot d\vec{l} = \mu_0 I \]
This expression corresponds to IV in List-II. (Note: The negative sign in the question, \( \oint \vec{B} \cdot d\vec{l} = -\mu_0 I \), would arise from a specific choice of direction for the line element \(d\vec{l}\) opposite to the convention of the right-hand rule, but it represents the same physical law). Therefore, C matches with IV.
Step 4: Match 'D. Gauss's law of electrostatics'
Gauss's law for electrostatics relates the electric flux through a closed surface to the enclosed charge. The equation is:
\[ \oint \vec{E} \cdot d\vec{a} = \frac{1}{\epsilon_0} \int \rho dV \]
This expression is listed as I in List-II. Therefore, D matches with I.
The correct matching is as follows:
This corresponds to the combination: A-II, B-III, C-IV, D-I.
A black body is at a temperature of 2880 K. The energy of radiation emitted by this body with wavelength between 499 nm and 500 nm is U1, between 999 nm and 1000 nm is U2 and between 1499 nm and 1500 nm is U3. The Wien's constant, b = 2.88×106 nm-K. Then,




What will be the equilibrium constant of the given reaction carried out in a \(5 \,L\) vessel and having equilibrium amounts of \(A_2\) and \(A\) as \(0.5\) mole and \(2 \times 10^{-6}\) mole respectively?
The reaction : \(A_2 \rightleftharpoons 2A\)