A current-carrying coil is placed in an external uniform magnetic field. The coil is free to turn in the magnetic field. What is the net force acting on the coil? Obtain the orientation of the coil in stable equilibrium. Show that in this orientation the flux of the total field (field produced by the loop + external field) through the coil is maximum.
A coil of 60 turns and area \( 1.5 \times 10^{-3} \, \text{m}^2 \) carrying a current of 2 A lies in a vertical plane. It experiences a torque of 0.12 Nm when placed in a uniform horizontal magnetic field. The torque acting on the coil changes to 0.05 Nm after the coil is rotated about its diameter by 90°. Find the magnitude of the magnetic field.
Match List-I with List-II
\[\begin{array}{|l|l|} \hline \text{List-I (Soil component)} & \text{List-II (Definition)} \\ \hline (A)~\text{Azonal soils} & (I)~\text{An individual natural aggregate of soil particles.} \\ (B)~\text{Regoliths} & (II)~\text{Organisms living in the soil or ground} \\ (C)~\text{Ped} & (III)~\text{Soils have uniformity from the top-surface to the base, and do not have well-developed soil horizons.} \\ (D)~\text{Edaphons} & (IV)~\text{Zone of loose and unconsolidated weathered rock materials.} \\ \hline \end{array}\]
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Match List-I with List-II
\[\begin{array}{|l|l|} \hline \text{List I Content of humus} & \text{List II Percentage of contents} \\ \hline \text{(A) Carbon} & \text{(I) 35-40\%} \\ \hline \text{(B) Oxygen} & \text{(II) ~5\%} \\ \hline \text{(C) Hydrogen} & \text{(III) 55-60\%} \\ \hline \text{(D) Nitrogen} & \text{(IV) 15\%} \\ \hline \end{array}\]
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