Goodmarks
Sign in

Physics · Torque experienced by a current loop in a uniform magnetic field: Moving coil galvanometer, its sensitivity and conversion to ammeter and voltmeter

A planar coil of area carrying an anti-clockwise current 2 A is placed in an ext

A planar coil of area \( 7 \mathrm{m}^{2} \) carrying an anti-clockwise current 2 A is placed in an extemal magnetic field \( \vec{B}=(0.2 \hat{i}+ \) \( 0.2 \hat{j}-0.3 \hat{k}), \) such that the normal to the plane is along the \( \operatorname{line}(3 \hat{i}-5 \hat{j}+ \) 4 \( \hat{k} \) ). Select correct statements from the following. ( Consider Normal of the coil and Magnetic moment vectors to be in the same direction This question has multiple correct options

  • A. The potential energy of the coil in the given orientation is 6.4
  • B. The angle between the normal (positive) to the coil and the external magnetic field is \( \cos ^{-1}(0.57) \)
  • C. The potential energy of the coil in the given orientation is 3.2
  • D. The magnitude of magnetic moment of the coil is about \( 14 A m^{2} \)

Step-by-step solution

Magnetic moment magnitude = current × area = 2 A × 7 m² = 14 A m². The direction is along the normal, but magnitude is exact. Options A and B are incorrect (A gives double the computed potential energy, B gives wrong angle). Option C gives an approximate potential energy (3.2 vs exact ~3.17), but D is exactly correct.
Practise more in this unitView MCQsSign up for full question bank

Related MCQs