MCQMediumJEE 2026Dimensions & Dimensional Analysis

JEE Physics 2026 Question with Solution

Match the LIST-I with LIST-II:

List-IList-IIA.Magnetic inductionI.MLT2A2B.Magnetic fluxII.ML2T2A2C.Magnetic permeabilityIII.ML0T2A1D.Self inductanceIV.ML2T2A1\begin{array}{|c|l|c|l|} \hline \text{List-I} & & \text{List-II} & \\ \hline \text{A.} & \text{Magnetic induction} & \text{I.} & M L T^{-2} A^{-2} \\ \text{B.} & \text{Magnetic flux} & \text{II.} & M L^{2} T^{-2} A^{-2} \\ \text{C.} & \text{Magnetic permeability} & \text{III.} & M L^{0} T^{-2} A^{-1} \\ \text{D.} & \text{Self inductance} & \text{IV.} & M L^{2} T^{-2} A^{-1} \\ \hline \end{array}

Choose the correct answer from the options given below:

  • A

    A-III, B-IV, C-II, D-I

  • B

    A-I, B-III, C-IV, D-II

  • C

    A-IV, B-III, C-I, D-II

  • D

    A-III, B-IV, C-I, D-II

Answer

Correct answer:D

Step-by-step solution

Standard Method

Given: Match magnetic quantities with their dimensional formulae.

Find: The correct correspondence between LIST-I and LIST-II.

Step 1: Magnetic induction BB. Magnetic induction is force per unit current per unit length.

[B]=ML0T2A1[B] = M L^{0} T^{-2} A^{-1}

Hence, A \rightarrow III.

Step 2: Magnetic flux Φ\Phi. Magnetic flux is given by B×areaB \times \text{area}.

[Φ]=(ML0T2A1)×L2=ML2T2A1[\Phi] = (M L^{0} T^{-2} A^{-1}) \times L^{2} = M L^{2} T^{-2} A^{-1}

Hence, B \rightarrow IV.

Step 3: Magnetic permeability μ\mu. From B=μHB = \mu H,

[μ]=[B][H]=ML0T2A1AL1=MLT2A2[\mu] = \frac{[B]}{[H]} = \frac{M L^{0} T^{-2} A^{-1}}{A L^{-1}} = M L T^{-2} A^{-2}

Hence, C \rightarrow I.

Step 4: Self inductance LL. Self inductance is flux per unit current.

[L]=ML2T2A1A=ML2T2A2[L] = \frac{M L^{2} T^{-2} A^{-1}}{A} = M L^{2} T^{-2} A^{-2}

Hence, D \rightarrow II.

Conclusion: The correct matching is A-III, B-IV, C-I, D-II. Therefore, the correct option is D.

Stepwise Dimensional Derivation

Given: The quantities are magnetic induction, magnetic flux, magnetic permeability, and self inductance.

Find: Their dimensional matches.

Use basic definitions instead of memorizing formulae.

For magnetic induction,

B=FIlB = \frac{F}{I \, l}

So,

[B]=MLT2AL=ML0T2A1[B] = \frac{M L T^{-2}}{A \, L} = M L^{0} T^{-2} A^{-1}

Therefore, A matches III.

For magnetic flux,

Φ=B×area\Phi = B \times \text{area}

Thus,

[Φ]=(ML0T2A1)×L2=ML2T2A1[\Phi] = (M L^{0} T^{-2} A^{-1}) \times L^{2} = M L^{2} T^{-2} A^{-1}

Therefore, B matches IV.

For magnetic permeability, use

B=μHB = \mu H

and magnetic field strength has dimensions

[H]=AL1[H] = A L^{-1}

Hence,

[μ]=ML0T2A1AL1=MLT2A2[\mu] = \frac{M L^{0} T^{-2} A^{-1}}{A L^{-1}} = M L T^{-2} A^{-2}

Therefore, C matches I.

For self inductance,

L=ΦIL = \frac{\Phi}{I}

So,

[L]=ML2T2A1A=ML2T2A2[L] = \frac{M L^{2} T^{-2} A^{-1}}{A} = M L^{2} T^{-2} A^{-2}

Therefore, D matches II.

Hence the final arrangement is A-III, B-IV, C-I, D-II, which corresponds to option D.

Note: The raw option numbering on the source corresponds to option (4), and that is labeled D here.

Common mistakes

  • Confusing magnetic induction BB with magnetic field strength HH. This is wrong because BB and HH have different dimensions. Always derive [B][B] from force on a current-carrying conductor and use B=μHB = \mu H only after identifying [H]=AL1[H] = A L^{-1}.

  • Forgetting to multiply magnetic induction by area while finding magnetic flux. This is wrong because flux is Φ=B×area\Phi = B \times \text{area}, not just BB. Include the extra factor of L2L^{2} to get the correct dimensions.

  • Mixing the symbol LL for length with LL for self inductance. This is wrong because in dimensional formulae the exponent on capital LL denotes length, while self inductance is the physical quantity being evaluated. Use context carefully before matching.

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