Basic Properties of Magnets
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Basic Properties of Magnets

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Questions and Answers

What is the name given to the space around a magnet where its influence can be felt?

  • Magnetic induction
  • Magnetic field (correct)
  • Magnetic length
  • Magnetic axis

    • Which statement correctly describes the relationship between magnetic poles?

  • Magnetic poles can exist independently.
  • Like poles repel each other, while unlike poles attract. (correct)
  • Magnetic poles can change their properties under certain conditions.
  • Magnetic poles can only be found at the ends of magnets.

    • What is the magnetic induction phenomenon?

  • The ability of a magnet to attract any metallic object.
  • The common alignment of magnets when dropped together.
  • A magnet inducing magnetism in a magnetic substance placed nearby. (correct)
  • When two magnets interact to form a magnetic field.

    • What defines a uniform magnetic field?

    <p>A magnetic field that has the same magnitude and direction at all points.</p> Signup and view all the answers

    Which law describes the force of attraction or repulsion between two magnetic poles?

    <p>Coulomb's Law of Magnetic Force</p> Signup and view all the answers

    What is the distance between the two poles of a magnet called?

    <p>Magnetic length</p> Signup and view all the answers

    What phenomenon is described by a magnetic dipole?

    <p>Two equal and opposite magnetic poles separated by a small distance.</p> Signup and view all the answers

    Which of the following best describes the magnetic equator of a magnet?

    <p>The line perpendicular to the magnetic axis through the center of the magnet.</p> Signup and view all the answers

    What is the direction of the magnetic field at the equatorial point of a magnetic dipole?

    <p>From N-pole to S-pole</p> Signup and view all the answers

    How does the magnetic field at a point on the axial line compare to the magnetic field at the equatorial line?

    <p>It is twice at the axial line</p> Signup and view all the answers

    What does the torque acting on a magnetic dipole depend on?

    <p>The angle between magnetic axis and magnetic field</p> Signup and view all the answers

    What happens to the torque when the angle between the magnetic dipole and the magnetic field is 0°?

    <p>Torque is minimum</p> Signup and view all the answers

    What is the SI unit of magnetic moment?

    <p>Newton meter per Tesla</p> Signup and view all the answers

    Which of the following statements is true about the forces exerted on the poles of a magnet in a uniform magnetic field?

    <p>They are equal in magnitude and opposite in direction</p> Signup and view all the answers

    What is the expression for the torque on a magnetic dipole in a magnetic field?

    <p>Torque = Magnetic moment × Magnetic field strength</p> Signup and view all the answers

    In a uniform magnetic field, if the angle of the magnetic dipole is θ = 90°, what is the torque acting on it?

    <p>mB</p> Signup and view all the answers

    According to the Bohr model, the magnetic dipole moment of a revolving electron is equivalent to which of the following?

    <p>Current loop area</p> Signup and view all the answers

    What is the formula for the magnetic dipole moment of a current loop?

    <p>Ampere turns × Loop area</p> Signup and view all the answers

    What is the gyro magnetic ratio value derived from the ratio of the magnetic moment to the angular momentum of an electron?

    <p>8.8 × 10^10 C kg^-1</p> Signup and view all the answers

    What does Gauss's law in magnetism state about the net magnetic flux through a closed surface?

    <p>It is always zero.</p> Signup and view all the answers

    What is defined as the minimum magnetic moment associated with an electron in its first orbit of a hydrogen atom?

    <p>Bohr magneton</p> Signup and view all the answers

    Which of the following describes a consequence of Gauss's law in magnetism?

    <p>There are no sources or sinks of magnetic field inside a closed surface.</p> Signup and view all the answers

    How is the total magnetic moment of an electron defined?

    <p>As the vector sum of orbital and intrinsic magnetic moments.</p> Signup and view all the answers

    What is the relation between angular momentum and the allowed orbits in the Bohr model?

    <p>It is an integral multiple of h/2π.</p> Signup and view all the answers

    What is the expression for the torque experienced by a magnetic dipole in a magnetic field at an angle θ?

    <p>$ au = mB ext{sin} θ$</p> Signup and view all the answers

    At which angle θ is the potential energy of a magnetic dipole at a minimum?

    <p>0°</p> Signup and view all the answers

    What is the potential energy formula for a magnetic dipole when positioned at an angle θ?

    <p>$U = -mB ext{cos} θ$</p> Signup and view all the answers

    When is the potential energy U of a magnetic dipole zero?

    <p>At θ = 90°</p> Signup and view all the answers

    Which formula determines the magnetic dipole moment for a current loop with N turns?

    <p>$ ext{Magnetic Moment} = NIA$</p> Signup and view all the answers

    What happens to the potential energy when a magnetic dipole is aligned anti-parallel to the magnetic field?

    <p>It becomes positive</p> Signup and view all the answers

    How is the magnetic field from a circular current loop at a distance r from the center described?

    <p>It has the same distance dependence as the electric dipole moment.</p> Signup and view all the answers

    Which statement about the equilibrium states of a magnetic dipole is true?

    <p>Stable equilibrium occurs when θ = 0°.</p> Signup and view all the answers

    What is the magnetic field in vacuum that induces magnetism called?

    <p>Magnetizing field</p> Signup and view all the answers

    How is the magnetic field inside a magnetic material defined?

    <p>The sum of the external magnetizing field and the induced magnetic field</p> Signup and view all the answers

    What is the equation for the magnetizing field intensity?

    <p>H = n I</p> Signup and view all the answers

    What are the dimensions of magnetic intensity?

    <p>L^-1 A</p> Signup and view all the answers

    How is intensity of magnetization defined?

    <p>The ratio of the magnetic moment to the volume of the material</p> Signup and view all the answers

    In a toroidal solenoid, what is the effect of placing it in a magnetic material?

    <p>It increases the alignment of atomic current loops.</p> Signup and view all the answers

    What does the magnetic moment developed per unit volume measure?

    <p>Intensity of magnetization</p> Signup and view all the answers

    What is the SI unit for magnetic intensity?

    <p>Ampere meter^-1 (A m^-1)</p> Signup and view all the answers

    Study Notes

    Basic Properties of Magnets

    • A magnet attracts small pieces of iron, cobalt, and nickel.
    • When freely suspended, a magnet aligns itself in the geographical north-south direction.
    • Like poles repel while unlike poles attract.
    • Magnetic poles always exist as pairs.
    • Magnetic induction occurs when a magnet induces magnetism in a nearby magnetic substance.

    Important Definitions in Magnetism

    • Magnetic Field: The surrounding space where a magnet's influence is felt.
    • Uniform Magnetic Field: A magnetic field with the same magnitude and direction throughout a region.
    • Magnetic Poles: Regions of concentrated magnetic strength where attraction is strongest.
    • Magnetic Axis: The line connecting the two poles of a magnet.
    • Magnetic Equator: The line perpendicular to the magnetic axis and passing through the center of the magnet.
    • Magnetic Length: The distance between the two poles, slightly less than the geometrical length.

    Coulomb's Law of Magnetic Force

    • States that the attraction or repulsion between two magnetic poles is proportional to the product of their pole strengths and inversely proportional to the square of the distance between them.
    • Defined mathematically, with force ( F ) corresponding to pole strengths ( p_1 ) and ( p_2 ) at a distance ( r ).

    Magnetic Dipole

    • An arrangement of two equal and opposite poles separated by a small distance.
    • The magnetic field at equatorial points in relation to a dipole is opposite to the dipole moment direction.

    Torque on a Magnetic Dipole

    • Torque is produced when a magnetic dipole is in a uniform magnetic field at an angle ( θ ).
    • The torque ( τ = \text{Force} \times \text{perpendicular distance} ).
    • At ( θ = 0°), torque is minimized; at ( θ = 90°), torque is maximized.

    Potential Energy of a Magnetic Dipole

    • Potential energy is stored when a dipole is rotated against the torque trying to align it with the magnetic field.
    • Potential energy is minimum when ( θ = 0°) and maximum when ( θ = 180°).

    Current Loop as a Magnetic Dipole

    • A circular loop of current behaves as a magnetic dipole with a defined magnetic moment.
    • Magnetic dipole moment of a current loop = ( NI \times A ) (N = number of turns, I = current, A = area).

    Magnetic Dipole Moment of a Revolving Electron

    • Electrons produce a magnetic dipole moment due to their circular motion around a nucleus, akin to a current loop.
    • The ratio of magnetic moment to angular momentum yields the gyro-magnetic ratio.

    Bohr Magneton

    • Defined as the magnetic moment associated with an electron due to its orbital motion in the first orbit of a hydrogen atom.

    Gauss's Law in Magnetism

    • States that the surface integral of a magnetic field over a closed surface is zero, indicating no isolated magnetic poles exist.

    Magnetizing Field

    • The external magnetic field that induces magnetism in materials.
    • The magnetic field within a toroidal solenoid is given by a specific formula based on the number of turns per unit length.

    Magnetic Induction and Magnetization

    • Occurs when a magnetic material is placed in an external magnetizing field, causing atomic magnetic moments to align.
    • The magnetic moment per unit volume is known as intensity of magnetization.

    Intensity of Magnetization

    • Defined as the magnetic moment developed per unit volume in a magnetizing field.
    • The intensity can also be expressed in terms of pole strength per unit area.

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    Basic Properties of Magnets PDF

    Description

    Explore the fundamental properties of magnets in this quiz. You'll learn about attractive and directive properties, the behavior of magnetic poles, and the phenomenon of magnetic induction. Test your understanding of how magnets operate and their effects on various materials.

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