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The dimensions [MLT2A2][MLT^{-2}A^{-2}] belong to the:

A

electric permittivity

B

magnetic flux

C

self-inductance

D

magnetic permeability

Step-by-Step Solution

Let us determine the dimensional formulae for the given physical quantities:

  1. Magnetic permeability (μ0\mu_0): The force per unit length between two parallel current-carrying conductors is given by Fl=μ0I1I22πd\frac{F}{l} = \frac{\mu_0 I_1 I_2}{2\pi d}. Rearranging for μ0\mu_0, we get μ0=F2πdI1I2l\mu_0 = \frac{F \cdot 2\pi d}{I_1 I_2 l}. Substituting the dimensions: Force [F]=[MLT2][F] = [MLT^{-2}], distance [d]=[L][d] = [L], length [l]=[L][l] = [L], and current [I]=[A][I] = [A]. Dimensions of μ0=[MLT2][L][A]2[L]=[MLT2A2]\mu_0 = \frac{[MLT^{-2}][L]}{[A]^2 [L]} = [MLT^{-2}A^{-2}].

  2. Electric permittivity (ε0\varepsilon_0): From Coulomb's law, F=14πε0q1q2r2    ε0=q1q24πFr2F = \frac{1}{4\pi\varepsilon_0} \frac{q_1 q_2}{r^2} \implies \varepsilon_0 = \frac{q_1 q_2}{4\pi F r^2}. Its dimensions are [AT]2[MLT2][L]2=[M1L3T4A2]\frac{[AT]^2}{[MLT^{-2}][L]^2} = [M^{-1}L^{-3}T^4A^2].

  3. Magnetic flux (ΦB\Phi_B): ΦB=BA\Phi_B = B \cdot A. The dimensions of magnetic field [B]=[MT2A1][B] = [MT^{-2}A^{-1}] and area [A]=[L2][A] = [L^2]. So, dimensions of ΦB=[ML2T2A1]\Phi_B = [ML^2T^{-2}A^{-1}].

  4. Self-inductance (LL): Energy stored in an inductor is U=12LI2    L=2UI2U = \frac{1}{2}LI^2 \implies L = \frac{2U}{I^2}. Its dimensions are [ML2T2][A]2=[ML2T2A2]\frac{[ML^2T^{-2}]}{[A]^2} = [ML^2T^{-2}A^{-2}].

Therefore, the dimensions [MLT2A2][MLT^{-2}A^{-2}] correspond to magnetic permeability .

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