Match List - I with List - II.
| List - I | List - II |
| (A) Magnetic dipole moment | (I) Weber/m2 |
| (B) Magnetic permeability | (II) Am (Ampere m) |
| (C) Pole strength | (III) Henry/m |
| (D) Magnetic flux density | (IV) Am2 (Ampere m2) |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → (A)-(IV), (B)-(III), (C)-(II), (D)-(I)
Each unit follows from the defining relation of the quantity.
(A) Magnetic dipole moment — this matches (IV) Am2 (Ampere m2). The magnetic moment of a current loop is current times area, \( m = IA \), so its unit is \( \mathrm{A\,m^{2}} \).
(B) Magnetic permeability — this matches (III) Henry/m. From the self-inductance of a long solenoid, \( L = \mu n^{2} A l \), \( \mu \) has the unit of inductance per unit length, \( \mathrm{H\,m^{-1}} \), the unit of \( \mu_0 = 4\pi\times10^{-7}\,\mathrm{H\,m^{-1}} \).
(C) Pole strength — this matches (II) Am (Ampere m). The dipole moment of a bar magnet is pole strength times magnetic length, \( m = q_m \times 2l \), so \( q_m = m/2l \) has the unit \( \mathrm{A\,m^{2}}/\mathrm{m} = \mathrm{A\,m} \).
(D) Magnetic flux density — this matches (I) Weber/m2. Magnetic flux density is flux per unit area, \( B = \Phi/A \), so its unit is \( \mathrm{Wb\,m^{-2}} \) (the tesla).