Free NEET Physics multiple-choice questions on Magnetism & Matter. Attempt each question and reveal the answer with a full explanation.
The potential energy of a magnetic dipole is minimum when it is: Parallel to the magnetic field Antiparallel to the magnetic field Perpendicular to the magnetic field At 45 to the magnetic field Work done in rotating a magnetic dipole from 90 to 180 in a uniform magnetic field B is: MB 2MB -MB Zero The magnetic susceptibility of vacuum is: Zero 1 -1 Infinity The magnetic susceptibility of a diamagnetic substance varies with absolute temperature T as: Independent of T T -1 T T -2 The magnetic susceptibility of a material is -0.5 10 -5 . The material is: Diamagnetic Paramagnetic Ferromagnetic Non-magnetic The work done in rotating a bar magnet from its position of stable equilibrium to unstable equilibrium in a uniform magnetic field B is: 2MB MB Zero -2MB Curie's law for paramagnetic substances states that the magnetic susceptibility is related to absolute temperature T as: 1/T T T 2 1/T 2 The magnetic susceptibility of a paramagnetic substance is 3 10 -4 at 300 K. Its susceptibility at 600 K will be: 1.5 10 -4 6 10 -4 3 10 -4 0.75 10 -4 The magnetic susceptibility of a substance is -0.0001 . This substance is: Diamagnetic Paramagnetic Ferromagnetic Ferrimagnetic Which of the following properties is characteristic of a diamagnetic substance? Susceptibility is negative and small. Susceptibility is positive and large. Susceptibility is positive and small. It is attracted by a strong magnet. The hysteresis loss per unit volume for a ferromagnetic material is equal to: Area of the B-H loop Breadth of the B-H loop Square of the area of the B-H loop Half the area of the B-H loop The work done in rotating a magnetic dipole of moment M from its position of stable equilibrium to a position where it is perpendicular to a uniform magnetic field B is: MB 2MB MB/2 Zero At the magnetic equator, the value of the angle of dip is: 0 45 90 180 A superconducting material exhibits: Perfect diamagnetism Perfect paramagnetism Perfect ferromagnetism Non-magnetic behavior The magnetic susceptibility of a material is 499 . The relative permeability of the material is: 500 498 500 4π 10 -7 1 Which of the following materials is most suitable for making a permanent magnet? Steel Soft iron Copper Aluminum The magnetic susceptibility is negative for: Diamagnetic materials only Paramagnetic materials only Ferromagnetic materials only Paramagnetic and ferromagnetic materials The vertical component of Earth's magnetic field at a place is 3 times the horizontal component. The angle of dip at that place is: 60 30 45 0 At the Curie temperature, a ferromagnetic material becomes: Paramagnetic Diamagnetic Non-magnetic Anti-ferromagnetic The magnetic field due to a small bar magnet at a point on its axis at a distance r is B . The magnetic field at the same distance r on the equator of the magnet is: B/2 2B B B/4 At the magnetic equator of the Earth, the vertical component of the Earth's magnetic field is: Zero Maximum Equal to the horizontal component Infinity At a certain place, the horizontal component of Earth's magnetic field is B 0 and the angle of dip is 45 ∘ . The total magnetic field of Earth at that place is: √2 B 0 B 0 / √2 2 B 0 B 0 The magnetic susceptibility of a perfectly diamagnetic substance (superconductor) is: -1 0 1 Infinity A permanent magnet is best made from a material having: High retentivity and high coercivity High retentivity and low coercivity Low retentivity and high coercivity Low retentivity and low coercivity For a short bar magnet, the ratio of the magnetic field at an axial point to that at an equatorial point at the same distance r is: 2 : 1 1 : 2 1 : 1 4 : 1 The magnetic susceptibility of a diamagnetic substance: is independent of temperature. increases with temperature. decreases with temperature. is directly proportional to the square root of temperature. Which of the following materials has a negative magnetic susceptibility? Copper Aluminum Iron Nickel The work done per unit volume per cycle of magnetization in a ferromagnetic material is equal to: Area of the hysteresis loop Twice the area of the hysteresis loop Half the area of the hysteresis loop Zero Which of the following properties is used to distinguish between a paramagnetic and a diamagnetic substance when placed in a non-uniform magnetic field? Direction of movement relative to the field gradient Density of the material Electrical conductivity Color of the substance If the magnetic susceptibility of a material is , then the relation between relative permeability r and is: r = 1 + = 1 + r r = - 1 r = 1/ The magnetic susceptibility of a material is 4 10 -5 . This material is: Paramagnetic Diamagnetic Ferromagnetic Non-magnetic A compass needle is placed in a horizontal plane. At which of the following places will it stay in any direction? Magnetic poles Magnetic equator Geographic poles Geographic equator Relative permeability of a substance is 0.99. The substance is: Diamagnetic Paramagnetic Ferromagnetic Non-magnetic A magnetic dipole is in a state of unstable equilibrium in a uniform magnetic field. Its potential energy is: +MB -MB Zero MB/2 If the angle of dip at a certain place is 30 and the horizontal component of Earth's magnetic field is H , the intensity of the total magnetic field is: 2H/ 3 H/2 H 3 H 3 /2 The area under the hysteresis loop of a ferromagnetic material represents: Energy dissipated per unit volume per cycle Magnetic flux per unit area Magnetic potential energy Retentivity of the material When a magnet is heated above its Curie temperature, it: Becomes paramagnetic Becomes diamagnetic Becomes more strongly ferromagnetic Its magnetic moment increases Which of the following materials is most likely to show a relative permeability r = 1.00002 ? Aluminum (Paramagnetic) Copper (Diamagnetic) Iron (Ferromagnetic) Bismuth (Diamagnetic) The magnetic susceptibility of a paramagnetic material at -73 ∘ C is 0.0075. Its value at -173 ∘ C will be: 0.015 0.00375 0.01 0.005 A magnetic needle suspended horizontally by a silk thread oscillates in the Earth's magnetic field. If the temperature of the needle is increased to the Curie point, then: The needle stops oscillating The time period decreases The time period remains same The needle oscillates faster Two identical bar magnets are placed such that their axes are perpendicular to each other and their centers coincide. If the magnetic moment of each magnet is M , the net magnetic moment of the system is: 2 M 2M M/ 2 Zero The work done in rotating a bar magnet of magnetic moment M from the direction of a uniform magnetic field B to a direction opposite to the field is: 2MB MB Zero -MB Materials suitable for making electromagnets should have: High permeability and low retentivity High permeability and high retentivity Low permeability and high retentivity Low permeability and low retentivity If a magnet is cut into two equal halves along its length, then for each part: Pole strength becomes half, magnetic moment becomes half Pole strength remains same, magnetic moment becomes half Pole strength becomes half, magnetic moment remains same Both remain same A small bar magnet has a magnetic moment M . The ratio of the magnetic field at a point P at a distance r on the axis to that at a point Q at a distance 2r on the axis is: 8:1 4:1 2:1 1:1 Which of the following statements is true for a diamagnetic substance? Its susceptibility is independent of temperature Its susceptibility is inversely proportional to temperature Its susceptibility is directly proportional to temperature Its susceptibility increases with temperature The magnetic susceptibility of a ferromagnetic material above its Curie temperature T c follows the relation: 1 T - T c T - T c 1 T is constant At the geographic poles of the Earth, the horizontal component of the Earth's magnetic field is approximately: Zero Maximum Infinite Same as at the equator Which of the following materials exhibits the Meissner effect? Superconductors Ferromagnetic materials Paramagnetic materials Diamagnetic materials A paramagnetic liquid is poured into a U-tube and one arm is placed between the pole pieces of a strong magnet. The liquid level in that arm will: Rise Fall Remain the same Oscillate A dip circle is at right angles to the magnetic meridian. What will be the apparent dip at this place? 90 0 45 Equal to the real dip What is the magnetic susceptibility of a superconductor? -1 0 1 Infinity A bar magnet of magnetic moment M is placed at right angles to a magnetic meridian. The force required to keep it at an angle with the meridian is proportional to: 1/ At a certain location in Africa, a compass points 12 west of geographic north. The north tip of the magnetic needle of a dip circle placed in the plane of magnetic meridian points 60 above the horizontal. The horizontal component of Earth's field is measured to be 0.16 G. The magnitude of Earth's total magnetic field at that location is: 0.32 G 0.16 G 0.08 G 0.64 G Which of the following is correct regarding the hysteresis loop for soft iron as compared to steel? Area is smaller Retentivity is lower Coercivity is higher Area is larger Which of the following is the most suitable reason for the use of soft iron as a core in transformers? High permeability and low hysteresis loss Low permeability and high hysteresis loss High retentivity and high coercivity Low retentivity and low coercivity only A bar magnet is placed north-south with its north pole pointing towards geographic north. The neutral points are located: On the equatorial line On the axial line At 45 to the axis At the poles of the magnet A compass needle points 15 East of North. If the horizontal component of Earth's magnetic field is 0.32 G, the true North-South component of the field is: 0.32 15 G 0.32 15 G 0.32 15 G 0.32 G A tangent galvanometer shows a deflection of 45 for a current of 0.5 A. For what current will the deflection be 60 ? 0.5 3 A 0.5/ 3 A 1.5 A 1.0 A If a bar magnet is placed in the magnetic meridian with its North Pole pointing towards the Geographic South, the neutral points are located on: The axial line The equatorial line At an angle of 45 to the axis None of these The apparent dip at a place is 1 when the dip circle is in a plane making angle with the magnetic meridian. If the true dip is , then: = 1 = 1 / 1 = = 1 A bar magnet of magnetic moment M is placed in a uniform magnetic field B . The work done in rotating the magnet from the direction of the field to an angle is W . The torque acting on the magnet in this new position is: W ( /2) W ( /2) W W The domains in a ferromagnetic material typically have a size of about: 1 mm 1 nm 10 cm 1 m The magnetic moment of a short bar magnet is 1.6 Am 2 . It is placed in the magnetic meridian with its north pole pointing north. The neutral point is obtained at 20 cm from the center of the magnet. The horizontal component of Earth's magnetic field is ( 10 -7 SI units): 2 10 -4 T 4 10 -4 T 0.5 10 -4 T 1 10 -4 T The true dip at a place is . If the dip circle is placed in a plane inclined at an angle with the magnetic meridian, the apparent dip ' is given by: ' = / ' = ' = ' = / Which property of soft iron makes it suitable for the core of a transformer? High permeability and low hysteresis loss Low permeability and high retentivity High coercivity and high retentivity Low coercivity and high hysteresis loss The SI unit of magnetic coercivity is: A m -1 T Wb A m 2 The relative permeability r of a substance is 1.0001 . This substance is: Paramagnetic Diamagnetic Ferromagnetic Non-magnetic