PYQ Vault
EbooksTutor

Work done in rotating a magnetic dipole or current coil in a uniform field

This type of question, asked 5 times: 26 Jun 2022, 31 Jan 2023, 4 Apr 2024, 6 Apr 2024, 24 Jan 2026 S1. All 6 questions below, oldest first.

Try each one first, then open its answer.

  1. Question 1

    26 Jun 2022

    102
    A bar magnet having a magnetic moment of 2.0×2.0 \times 105JT−110^{5}JT^{- 1}, is placed along the direction of uniform magnetic field of magnitude B=14×10−5 TB = 14 \times10^{- 5}\text{ }T. The work done in rotating the magnet slowly through 60∘60^{\circ} from the direction of field is:

    Tap an option to check your answer.

  2. Question 2

    31 Jan 2023

    18
    A bar magnet with a magnetic moment 5.0Am25.0Am^{2} is placed in parallel position relative to a magnetic field of 0.4 T0.4\text{ }T. The amount of required work done in turning the magnet from parallel to antiparallel position relative to the field direction is___

    Tap an option to check your answer.

  3. Question 3

    4 Apr 2024

    93
    The magnetic moment of a bar magnet is 0.5Am20.5Am^{2}. It is suspended in a uniform magnetic field of 8×10−2 T8\times10^{- 2}\text{ }T. The work done in rotating it from its most stable to most unstable position is:

    Tap an option to check your answer.

  4. Question 4

    6 Apr 2024

    115
    A coil having 100 turns, area of 5×10−3 m25 \times10^{- 3}{\text{ }m}^{2}, carrying current of 1 mA1\text{ }mA is placed in uniform magnetic field of 0.20 T0.20\text{ }T such a way that plane of coil is perpendicular to the magnetic field. The work done in turning the coil through 90∘90^{\circ} is ____ μJ\mu J.

  5. Question 5

    6 Apr 2024

    28
    A circular coil having 200 turns, 2.5×10−4 m22.5 \times10^{- 4}{\text{ }m}^{2} area and carrying 100μA100\mu A current is placed in a uniform magnetic field of 1 T1\text{ }T. Initially the magnetic dipole moment (M→)(\overrightarrow{M}) was directed along B→\overrightarrow{B}. Amount of work, required to rotate the coil through 90∘90^{\circ} from its initial orientation such that M→\overrightarrow{M} becomes perpendicular to B→\overrightarrow{B}, is ___________ μJ\mu J.

  6. Question 6

    24 Jan 2026 S1

    21
    A short bar magnet placed with its axis at 30∘30^{\circ} with an external field of 800 Gauss, experiences a torque of 0.016 N.m. The work done in moving it from most stable to most unstable position is α×10−3 J\alpha \times 10^{- 3}\text{ }J. The value of α\alpha is ____\_\_\_\_ .