Physics · Units, Dimensions & Error Analysis

JEE Main 2024 — 6 April, Shift 1 — Question 41

Match List I with List II

LIST ILIST II
A.TorqueI.[M1  ⁣ ⁣  ⁣ ⁣ L1  ⁣ ⁣  ⁣ ⁣ T−2  ⁣ ⁣  ⁣ ⁣ A−2]\left[ {{\text{M}}^{1}}\text{ }\!\!~\!\!\text{ }{{\text{L}}^{1}}\text{ }\!\!~\!\!\text{ }{{\text{T}}^{-2}}\text{ }\!\!~\!\!\text{ }{{\text{A}}^{-2}} \right]
B.Magnetic fieldII.[L2  ⁣ ⁣  ⁣ ⁣ A1]\left[ {{\text{L}}^{2}}\text{ }\!\!~\!\!\text{ }{{\text{A}}^{1}} \right]
C.Magnetic momentIII.[M1  ⁣ ⁣  ⁣ ⁣ T−2  ⁣ ⁣  ⁣ ⁣ A−1]\left[ {{\text{M}}^{1}}\text{ }\!\!~\!\!\text{ }{{\text{T}}^{-2}}\text{ }\!\!~\!\!\text{ }{{\text{A}}^{-1}} \right]
D.Permeability of free spaceIV.[M1  ⁣ ⁣  ⁣ ⁣ L2  ⁣ ⁣  ⁣ ⁣ T−2]\left[ {{\text{M}}^{1}}\text{ }\!\!~\!\!\text{ }{{\text{L}}^{2}}\text{ }\!\!~\!\!\text{ }{{\text{T}}^{-2}} \right]

Choose the correct answer from the options given below :

  1. Option A:

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

  2. Option B:

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

    Correct
  3. Option C:

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

  4. Option D:

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

Answer: B

Step-by-step solution

[τ⃗]=[r→×F→]=[ML2 T−2][\vec{\tau}]=[\overrightarrow{\mathrm{r}} \times \overrightarrow{\mathrm{F}}]=\left[\mathrm{ML}^{2} \mathrm{~T}^{-2}\right]

[F]=[qVB][\mathrm{F}]=[\mathrm{qVB}] ⇒B=(FqV)=[MLT−2ATLT−1]=[MA−1 T−2]\Rightarrow \mathrm{B}=\left(\frac{\mathrm{F}}{\mathrm{qV}}\right)=\left[\frac{\mathrm{MLT}^{-2}}{\mathrm{ATLT}^{-1}}\right]=\left[\mathrm{MA}^{-1} \mathrm{~T}^{-2}\right] [M]=[I×A]=[AL2][\mathrm{M}]=[\mathrm{I} \times \mathrm{A}]=\left[\mathrm{AL}^{2}\right]

B=μ04πIdlsin⁡θr2B=\frac{\mu_{0}}{4 \pi} \frac{\mathrm{Idl} \sin \theta}{\mathrm{r}^{2}} ⇒[μ]=[Br2Idl]=[MT−2 A−1×L2AL]=[MLT−2 A−2]\begin{aligned} \Rightarrow[\mu]=\left[\frac{\mathrm{Br}^{2}}{\mathrm{Idl}}\right] & =\left[\frac{\mathrm{MT}^{-2} \mathrm{~A}^{-1} \times \mathrm{L}^{2}}{\mathrm{AL}}\right] & =\left[\mathrm{MLT}^{-2} \mathrm{~A}^{-2}\right]\end{aligned}

Answer key and solution verified before publishing.

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Exam
JEE Main 2024
Subject
Physics
Chapter
Units, Dimensions & Error Analysis
Topic
Units and Dimensions Analysis