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NEET-XII-Physics

05: Magnetism And Matter

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  • #8
    A closely wound solenoid of 2000 turns and area of cross-section 1.6 × 10-4 m2, carrying a current of 4.0 A, is suspended through its centre allowing it to turn in a horizontal plane.
    (a) What is the magnetic moment associated with the solenoid?
    (b) What is the force and torque on the solenoid if a uniform horizontal magnetic field of 7.5 × 10-2 T is set up at an angle of 30° with the axis of the solenoid?
    (a) What is the magnetic moment associated with the solenoid?
    (b) What is the force and torque on the solenoid if a uniform horizontal magnetic field of 7.5 × 10-2 T is set up at an angle of 30° with the axis of the solenoid?
    Ans : Number of turns on the solenoid, n = 2000

    Area of cross-section of the solenoid, A = 1.6 × 10-4 m2

    Current in the solenoid, I = 4 A
    (a) The magnetic moment along the axis of the solenoid is calculated as:

    M = nAI

    = 2000 × 1.6 × 10-4 × 4

    = 1.28 Am2
    (b) Magnetic field, B = 7.5 × 10-2 T

    Angle between the magnetic field and the axis of the solenoid, θ = 30°

    Torque,



    Since the magnetic field is uniform, the force on the solenoid is zero. The torque on the solenoid is
    (a) The magnetic moment along the axis of the solenoid is calculated as:

    M = nAI

    = 2000 × 1.6 × 10-4 × 4

    = 1.28 Am2
    (b) Magnetic field, B = 7.5 × 10-2 T

    Angle between the magnetic field and the axis of the solenoid, θ = 30°

    Torque,



    Since the magnetic field is uniform, the force on the solenoid is zero. The torque on the solenoid is
  • #8-a
    What is the magnetic moment associated with the solenoid?
    Ans : The magnetic moment along the axis of the solenoid is calculated as:

    M = nAI

    = 2000 × 1.6 × 10-4 × 4

    = 1.28 Am2
  • #8-b
    What is the force and torque on the solenoid if a uniform horizontal magnetic field of 7.5 × 10-2 T is set up at an angle of 30° with the axis of the solenoid?
    Ans : Magnetic field, B = 7.5 × 10-2 T

    Angle between the magnetic field and the axis of the solenoid, θ = 30°

    Torque,



    Since the magnetic field is uniform, the force on the solenoid is zero. The torque on the solenoid is