12th Class Physics Magnetism Question Bank

done MCQ - Magnetism and Matter Total Questions - 54

• question_answer1)
  Which of the following is correct about magnetic monopole?
  A)
  Magnetic monopole exist. done clear
  B)
  Magnetic monopole does not exist. done clear
  C)
  Magnetic monopole have constant value of monopole momentum.                                 done clear
  D)
  The monopole momentum increases due to increase at its distance from the field.                               done clear
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• question_answer2)
                                 Which of the following statements is true?
  A)
  A freely suspended magnet comes to rest in north-south direction.                                  done clear
  B)
  Opposite poles of magnets attract each other.           done clear
  C)
  The Earth behaves as a giant magnet.                 done clear
  D)
  Allot the above                                    done clear
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• question_answer3)
  A stationary magnet does not interact with:
  A)
  iron rod                         done clear
  B)
  moving charge            done clear
  C)
  magnet                          done clear
  D)
  stationary charge        done clear
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• question_answer4)
  Magnetic moment for a solenoid and corresponding bar magnet is:                                        
  A)
  equal for both                 done clear
  B)
  more for solenoid       done clear
  C)
    more for bar magnet   done clear
  D)
              None of these            done clear
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• question_answer5)
  Which of the following is not correct about the magnetic field lines?
  A)
  The magnetic field lines of a magnet form continuous closed loops.                                          done clear
  B)
              The tangent to the field line at a given point represents the direction of the net magnetic field B at that point.    done clear
  C)
              The larger number of field lines crossing per unit area, the stronger is the magnitude of the magnetic field B.        done clear
  D)
              The magnetic field lines may intersect to each other in certain conditions.                                  done clear
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• question_answer6)
  S.I. unit of magnetic pole strength is:
  A)
  ampere/metre                 done clear
  B)
              ampere-metre done clear
  C)
              volt/metre                      done clear
  D)
              \[ampere/metr{{e}^{2}}\] done clear
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• question_answer7)
  A wire is placed between the poles of two fixed bar magnets as shown in the figure. A small current in the wire is into the plane of the paper. The direction of the magnetic force on the wire is:
  A)
  \[\uparrow \]                               done clear
  B)
              \[\downarrow \] done clear
  C)
              \[\to \]                           done clear
  D)
              \[\leftarrow \] done clear
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• question_answer8)
  A solenoid of cross-sectional area \[2\times {{10}^{-4}}{{m}^{2}}\] and 900 turns has \[0.6\text{ }A{{m}^{2}}\] magnetic moment. Then the current flowing through it is:
  A)
  2.24 A                           done clear
  B)
              2.34 mA done clear
  C)
              3.33 A                           done clear
  D)
              3.33 mA done clear
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• question_answer9)
  A closely wound solenoid of 750 turns and area of cross-section of \[5\times {{10}^{-4}}{{m}^{2}}\] carries a current of 3.0A. Its associated magnetic moment is:
  A)
  \[4.12\,J\,{{T}^{-1}}\]              done clear
  B)
              \[3.12\,J\,{{T}^{-1}}\] done clear
  C)
              \[2.12\,J\,{{T}^{-1}}\]              done clear
  D)
              \[1.13\,J\,{{T}^{-1}}\] done clear
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• question_answer10)
  A closely wound solenoid of 1000 turns and area of cross-section \[1.4\times {{10}^{-4}}{{m}^{2}}\] carrying a current of 3A is suspended through its centre allowing it to turn in a horizontal plane. The magnetic moment associated with this solenoid is:
  A)
  \[0.22\,J\,{{T}^{-1}}\]              done clear
  B)
              \[0.32\,J\,{{T}^{-1}}\] done clear
  C)
              \[0.42\,J\,{{T}^{-1}}\]              done clear
  D)
              \[0.52\,J\,{{T}^{-1}}\] done clear
  View Solution play_arrow

• question_answer11)
  The magnetic dipole moment of a current carrying coil does not depend upon:
  A)
  number of turns of the coil. done clear
  B)
              cross-sectional area of the coil. done clear
  C)
              current flowing in the coil. done clear
  D)
              material of the turns of the coil. done clear
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• question_answer12)
  A circular coil of 300 turns and diameter 14 cm carries a current of 15 A. The magnitude of magnetic moment associated with the loop is:
  A)
  \[51.7\,\,J\,{{T}^{-1}}\]                        done clear
  B)
              \[69.2\,J\,{{T}^{-1}}\] done clear
  C)
              \[38.6\,J\,{{T}^{-1}}\]              done clear
  D)
              \[19.5\,J\,{{T}^{-1}}\] done clear
  View Solution play_arrow

• question_answer13)
  A closely wound solenoid of 3000 turns and area of cross- section \[2\times {{10}^{-4}}{{m}^{2}}\], carrying a current of 6 A is suspended through its centre allowing it to turn in a horizontal plane. The magnetic moment associated with this solenoid is: 
  A)
  \[1.2\,J{{T}^{-1}}\]                  done clear
  B)
              \[2.4\,J\,{{T}^{-1}}\]    done clear
  C)
              \[3.0\text{ }J\text{ }{{T}^{-1}}\]                      done clear
  D)
              \[3.6\text{ }J\text{ }{{T}^{-1}}\] done clear
  View Solution play_arrow

• question_answer14)
              A circular coil of 25 turns and radius of 12 cm is placed in a uniform magnetic field of 0.5 T normal to the plane of coil. If the current in the coil is 5A, then total torque experienced by the coil is:
  A)
  1.5 N m                         done clear
  B)
              2.5 N m     done clear
  C)
              3.5 N m                         done clear
  D)
              zero          done clear
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• question_answer15)
  A toroid of n turns, mean radius R and cross-sectional radius a carries current l. It is placed on a horizontal table taken as x-y plane. Its magnetic moment \[\overrightarrow{M}\]:                                                        (NCERT EXEMPLAR)
  A)
  is non-zero and points in the z-direction by symmetry. done clear
  B)
              points along the axis of the toroid \[(\overrightarrow{M}=M\widehat{\phi })\] done clear
  C)
              is zero, otherwise there would be a field falling as \[\frac{1}{{{r}^{3}}}\] at large distances outside the toroid.                       done clear
  D)
              is pointing radially outwards.                            done clear
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• question_answer16)
               The torque required to hold a small circular coil of 10 turns, area \[1\text{ }m{{m}^{2}}\] and carrying a current of \[\left( \frac{21}{44} \right)A\] in the middle of a long solenoid of \[{{10}^{3}}\] turns/m carrying a current of 2.5 A, with its axis perpendicular to the axis of the solenoid is:
  A)
  \[1.5\times {{10}^{-6}}Nm\]            done clear
  B)
              \[1.5\times {{10}^{-8}}Nm\] done clear
  C)
              \[1.5\times {{10}^{6}}Nm\]                  done clear
  D)
              \[1.5\times {{10}^{8}}Nm\] done clear
  View Solution play_arrow

• question_answer17)
  If a solenoid is having magnetic moment of \[0.65\text{ }J\text{ }{{T}^{-1}}\] is free to turn about the vertical direction and has a uniform horizontal magnetic field of 0.25 T applied. What is the magnitude of the torque on the solenoid when its axis makes an angle of \[30{}^\circ \] with the direction of applied field?
  A)
  0.075 Nm                      done clear
  B)
              0.080 Nm done clear
  C)
              0.081 Nm                      done clear
  D)
              0.091 Nm done clear
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• question_answer18)
  A circular coil is 100 turns, radius 10 cm carries a current of 5A. It is suspended vertically in a uniform horizontal magnetic field of 0.5 T and the field lines make an angle of \[60{}^\circ \] with the plane of the coil. The magnitude of the torque that must be applied on it to prevent it from turning is:
  A)
  2.93 Nm done clear
  B)
  3.43 Nm done clear
  C)
              3.93 Nm                        done clear
  D)
              4.93 Nm done clear
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• question_answer19)
  A dipole of magnetic moment \[\overrightarrow{M}=30\widehat{j}\,A{{m}^{2}}\] is placed along the y-axis in a uniform magnetic field \[\overrightarrow{B}=(2\widehat{i}\,+5\,\widehat{j})T\]. The torque acting on it is:
  A)
  \[-40\,\widehat{k}\,Nm\]             done clear
  B)
              \[-50\,\widehat{k}\,Nm\] done clear
  C)
              \[-60\,\widehat{k}\,Nm\]              done clear
  D)
              \[-70\,\widehat{k}\,Nm\] done clear
  View Solution play_arrow

• question_answer20)
  A uniform horizontal magnetic field of \[7.5\times {{10}^{-2}}T\] is set up at an angle of \[30{}^\circ \] with the axis of an solenoid and the magnetic moment associated with it is \[1.28\text{ }J{{T}^{-1}}\]. Then the torque on it is:
  A)
  \[4.8\times {{10}^{-2}}Nm\]     done clear
  B)
              \[1.6\times {{10}^{-2}}Nm\] done clear
  C)
              \[1.2\times {{10}^{-2}}Nm\]     done clear
  D)
              \[4.8\times {{10}^{-4}}Nm\] done clear
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• question_answer21)
  A magnetic dipole is under the influence of two magnetic fields. The angle between the field directions is \[60{}^\circ \] and one of the fields has a magnitude of \[1.2\times {{10}^{-2}}T\]. If the dipole comes to stable equilibrium at an angle of \[30{}^\circ \] with this field, then the magnitude of the field is:
  A)
  \[1.2\times {{10}^{-4}}T\]                    done clear
  B)
              \[2.4\times {{10}^{-4}}T\] done clear
  C)
              \[1.2\times {{10}^{-2}}T\]                    done clear
  D)
              \[2.4\times {{10}^{-2}}T\] done clear
  View Solution play_arrow

• question_answer22)
  Which of the following is not showing the essential difference between electrostatic shielding by a conducting shell and magnetostatic shielding?
  A)
  Electrostatic field lines can end on charges and conductors have free charges.    done clear
  B)
              Magnetic field lines can end but conductors cannot end them.                      done clear
  C)
              Lines of magnetic field cannot end on any material and perfect shielding is not possible.                        done clear
  D)
              Shells of high permeability materials can be used to divert lines of magnetic field from the interior region. done clear
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• question_answer23)
          The net magnetic flux through any closed surface, kept in a magnetic field is:
  A)
  zero                               done clear
  B)
              \[\frac{{{\mu }_{0}}}{4\pi }\] done clear
  C)
              \[4\pi {{\mu }_{0}}\]                 done clear
  D)
              \[\frac{4{{\mu }_{0}}}{\pi }\] done clear
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• question_answer24)
  The Earth behaves as a magnet with magnetic field pointing approximately from the geographic:
  A)
  North to South               done clear
  B)
              South to North done clear
  C)
              East to West             done clear
  D)
              West to East done clear
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• question_answer25)
  The strength of the Earth's magnetic field is:
  A)
  constant everywhere. done clear
  B)
              zero everywhere. done clear
  C)
              having very high value. done clear
  D)
              vary from place to place on the Earth's surface. done clear
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• question_answer26)
  Which of the following is responsible for the Earth's magnetic field?
  A)
  Convective currents in Earth's core. done clear
  B)
              Diversive current in Earth's core. done clear
  C)
              Rotational motion of Earth. done clear
  D)
              Translational motion of Earth. done clear
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• question_answer27)
  Which of the following independent quantities is not used to specify the Earth's magnetic field?
  A)
  Magnetic declination \[(\theta )\]. done clear
  B)
              Magnetic dip \[(\delta )\]. done clear
  C)
              Horizontal component of Earth's magnetic field \[({{B}_{H}})\]. done clear
  D)
              Vertical component of Earth's magnetic field \[({{B}_{V}})\]. done clear
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• question_answer28)
  If you made a map of magnetic field lines at Melbourne in Australia, then the magnetic field lines seem to be:
  A)
  go into the ground. done clear
  B)
              come out of the ground. done clear
  C)
              maintain a spiral path on the surface of Earth. done clear
  D)
              move on helical path above the surface of ground. done clear
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• question_answer29)
  The area of B-H Loop for soft iron, as compared to that for steel is:
  A)
  more                             done clear
  B)
              less       done clear
  C)
              equal                             done clear
  D)
              zero done clear
  View Solution play_arrow

• question_answer30)
  The horizontal and vertical components of Earth's magnetic field at a place are 0.3 G and 0.52 G. The Earth's magnetic field and the angle of dip are:
  A)
  \[0.3\text{ }G\text{ }and\text{ }\delta =30{}^\circ \]    done clear
  B)
  \[0.4\text{ }G\text{ }and\text{ }\delta \text{=}40{}^\circ \] done clear
  C)
              \[0.5\text{ }G\text{ }and\text{ }\delta \text{=5}0{}^\circ \]     done clear
  D)
  \[0.6\text{ }G\text{ }and\text{ }\delta \text{=6}0{}^\circ \] done clear
  View Solution play_arrow

• question_answer31)
  Let the magnetic field on Earth be modelled by that of a point magnetic dipole at the centre of Earth. The angle of dip at a point on the geographical equator is:
  A)
  always zero.              done clear
  B)
              positive, negative or zero. done clear
  C)
              unbounded              done clear
  D)
              always negative.         done clear
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• question_answer32)
    Consider the plane S formed by the dipole axis and the axis of Earth. If P be the point of intersection of the geographical and magnetic equators then the declination and dip angle at point P are:
  A)
  \[0{}^\circ ,11.3{}^\circ \]                    done clear
  B)
              \[11.3{}^\circ ,0{}^\circ \] done clear
  C)
              \[11.3{}^\circ ,11.3{}^\circ \]                done clear
  D)
              \[0{}^\circ ,0{}^\circ \] done clear
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• question_answer33)
  The magnetic field of the Earth can be modelled by that of a point dipole placed at the centre of the Earth. The dipole axis makes an angle of \[11.3{}^\circ \] with the axis of the Earth. At Mumbai, declination is nearly zero. Then.                                                                                                                           (NCERT EXEMPLAR)
  A)
  the declination varies between \[11.3{}^\circ W\] to \[11.3{}^\circ E\]. done clear
  B)
              the least declination is \[0{}^\circ \]. done clear
  C)
              the plane defined by dipole axis and the Earth axis passes through Greenwich. done clear
  D)
              declination averaged over the Earth must be always negative. done clear
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• question_answer34)
  The dip angle at a location in southern India is about \[18{}^\circ \]. Then the dip angle in Britain will be:
  A)
  greater than \[18{}^\circ \]          done clear
  B)
              lesser than \[18{}^\circ \] done clear
  C)
              equal to \[18{}^\circ \]              done clear
  D)
              zero done clear
  View Solution play_arrow

• question_answer35)
  The angle of dip at a certain place where the horizontal and vertical components of the Earth's magnetic field are equal is:
  A)
  \[30{}^\circ \]                           done clear
  B)
              \[75{}^\circ \]       done clear
  C)
              \[60{}^\circ \]                           done clear
  D)
              \[45{}^\circ \] done clear
  View Solution play_arrow

• question_answer36)
  The vertical component of Earth's magnetic field at a place is \[\sqrt{3}\] times the horizontal component, the value of angle of dip at this place is:
  A)
  \[30{}^\circ \]                           done clear
  B)
              \[45{}^\circ \]       done clear
  C)
              \[60{}^\circ \]                           done clear
  D)
              \[90{}^\circ \] done clear
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• question_answer37)
  At a certain location in Africa, compass points \[12{}^\circ \] west of geographic north. The north tip of magnetic needle of a dip circle placed in the plane of magnetic meridian points \[60{}^\circ \] above the horizontal. The horizontal component of Earth's magnetic field is measured to be 0.16 G. The magnitude of Earth's magnetic field at the location is:
  A)
  0.32 G                          done clear
  B)
              0.42 G      done clear
  C)
              4.2 G                            done clear
  D)
              3.2 G done clear
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• question_answer38)
  Assume the dipole model for Earth's magnetic field B which is given by the vertical component of magnetic field, \[{{B}_{V}}=\frac{{{\mu }_{0}}}{4\pi }\frac{2m\,\cos \theta }{{{r}^{3}}}\] and the horizontal component of magnetic field \[{{B}_{H}}=\frac{{{\mu }_{0}}}{4\pi }\frac{m\,sin\theta }{{{r}^{3}}}\], where \[\theta =90{}^\circ \] - latitude as measured from magnetic equator, then the loci of point for which dip angle is \[\pm \,45{}^\circ \].
  A)
  \[{{\tan }^{-1}}(3)\]                 done clear
  B)
              \[{{\tan }^{-1}}(2)\] done clear
  C)
              \[{{\tan }^{-1}}(0.5)\]               done clear
  D)
              \[{{\tan }^{-1}}(1)\] done clear
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• question_answer39)
     At a given place on Earth's surface the horizontal component of Earth*s magnetic field is \[2\times {{10}^{-5}}T\]and resultant magnetic field is \[4\times {{10}^{-5}}T\]. The angle of dip at this place is:
  A)
  \[30{}^\circ \]                           done clear
  B)
              \[60{}^\circ \]        done clear
  C)
              \[90{}^\circ \]                           done clear
  D)
              \[45{}^\circ \]        done clear
  View Solution play_arrow

• question_answer40)
  The Earth's magnetic field departs from its dipole shape substantially at large distance (greater than about 3000 km). The responsible factor for this distortion is:
  A)
  motion of ions in Earth's ionosphere.                    done clear
  B)
              motion of ions in Earth's atmosphere.                  done clear
  C)
              motion of ions in Earth's lithosphere.                    done clear
  D)
              motion of ions in the space.                           done clear
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• question_answer41)
                           In the magnetic meridian of a certain place the horizontal component of Earth's magnetic field is 0.25 G and dip angle is \[60{}^\circ \]. The magnetic field of the Earth at this location is:
  A)
  0.50 G                          done clear
  B)
              0.52 G     done clear
  C)
              0.54 G                          done clear
  D)
              0.56 G       done clear
  View Solution play_arrow

• question_answer42)
  The equatorial magnetic field of Earth is 0.4 G. Then its dipole moment on equator is:
  A)
  \[1.05\times {{10}^{23}}A{{m}^{2}}\]         done clear
  B)
              \[2.05\times {{10}^{23}}A{{m}^{2}}\]         done clear
  C)
              \[105\times {{10}^{21}}A{{m}^{2}}\]          done clear
  D)
              \[2.05\times {{10}^{21}}A{{m}^{2}}\]          done clear
  View Solution play_arrow

• question_answer43)
  A compass needle whose magnetic moment is \[60\text{ }A{{m}^{2}}\] pointing geographical north at a certain place where the horizontal component of Earth's magnetic field is \[40\times {{10}^{-6}}Wb{{m}^{-2}}\] experiences a torque of \[1.2\times {{10}^{-3}}\text{ }Nm\]. The declination of the place is:
  A)
  \[20{}^\circ \]                           done clear
  B)
              \[45{}^\circ \]        done clear
  C)
              \[~60{}^\circ \]                        done clear
  D)
              \[30{}^\circ \] done clear
  View Solution play_arrow

• question_answer44)
  A magnetising field of \[1500\text{ }A{{m}^{-1}}\] produces flux of \[2.4\times {{10}^{-5}}\] weber in a iron bar of the cross-sectional area of \[0.5\text{ }c{{m}^{2}}\]. The permeability of the iron bar is:
  A)
  245                               done clear
  B)
              250      done clear
  C)
              252                               done clear
  D)
              255 done clear
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• question_answer45)
  A solenoid has a core of a substance with relative permeability 600. What is the magnetic permeability of the given substance?
  A)
  \[20\pi \times {{10}^{-5}}N{{A}^{-2}}\]          done clear
  B)
              \[21\pi \times {{10}^{-5}}N{{A}^{-2}}\] done clear
  C)
              \[22\pi \times {{10}^{-5}}N{{A}^{-2}}\]          done clear
  D)
              \[24\pi \times {{10}^{-5}}N{{A}^{-2}}\] done clear
  View Solution play_arrow

• question_answer46)
  A permanent magnet in the shape of a thin cylinder of length 50 cm has intensity of magnetization \[{{10}^{6}}A{{m}^{-1}}\]. The magnetisation current is:
  A)
  \[5\times {{10}^{5}}A\]                 done clear
  B)
              \[6\times {{10}^{5}}A\] done clear
  C)
              \[5\times {{10}^{4}}A\]                        done clear
  D)
              \[6\times {{10}^{4}}A\] done clear
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• question_answer47)
  A domain in ferromagnetic iron in the form of cube is having \[5\times {{10}^{10}}\] atoms. If the side length of this domain is \[1.5\mu m\] and each atom has a dipole moment of \[8\times {{10}^{-24}}A{{m}^{2}}\], then magnetisation of domain is:
  A)
  \[118\times {{10}^{5}}A{{m}^{-1}}\]             done clear
  B)
              \[118\times {{10}^{4}}A{{m}^{-1}}\] done clear
  C)
              \[235\times {{10}^{4}}A{{m}^{-1}}\] done clear
  D)
              \[118\times {{10}^{5}}A{{m}^{-1}}\] done clear
  View Solution play_arrow

• question_answer48)
            A magnetising field of \[2\times {{10}^{3}}A{{m}^{-1}}\]produces a magnetic flux density of \[8\pi T\] in an iron rod. The relative permeability of the rod will be:
  A)
  \[{{10}^{2}}\]                         done clear
  B)
              1          done clear
  C)
              \[{{10}^{4}}\]                         done clear
  D)
              \[{{10}^{3}}\]         done clear
  View Solution play_arrow

• question_answer49)
  A permanent magnet in the shape of a thin cylinder of length 10 cm has magnetisation\[(M)={{10}^{6}}A{{m}^{-1}}\]. It’s magnetisation current \[{{l}_{M}}\] is:
  A)
  \[{{10}^{5}}A\]                       done clear
  B)
              \[{{10}^{6}}A\] done clear
  C)
              \[{{10}^{7}}A\]                       done clear
  D)
              \[{{10}^{8}}A\] done clear
  View Solution play_arrow

• question_answer50)
  A ring of mean radius 15 cm has 3500 turns of wire wound on a ferromagnetic core of relative permeability 800. The magnetic field in the core for a magnetising current of 1.2 A is:                                             
  A)
  2.48 T                           done clear
  B)
              3.48 T                    done clear
  C)
              4.48 T                           done clear
  D)
              5.48 T                    done clear
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• question_answer51)
  A solenoid has core of a material with relative permeability of 500. The windings of the solenoid are insulated from the core and carry a current of 2 A. If the number of turns is 1000 per meter, then magnetisation is:
  A)
  \[7.78\times {{10}^{5}}A{{m}^{-1}}\]            done clear
  B)
              \[8.88\times {{10}^{5}}A{{m}^{-1}}\] done clear
  C)
              \[9.98\times {{10}^{5}}A{{m}^{-1}}\]        done clear
  D)
              \[10.2\times {{10}^{5}}A{{m}^{-1}}\] done clear
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• question_answer52)
  A solenoid has core of a material with relative permeability 500 and its windings carry a current of 1.2 A. The number of turns of the solenoid is 500 per metre. The magnetisation of the material is nearly:
  A)
  \[2.5\times {{10}^{3}}A{{m}^{-1}}\]              done clear
  B)
              \[3\times {{10}^{5}}A{{m}^{-1}}\] done clear
  C)
              \[2.0\times {{10}^{3}}A{{m}^{-1}}\]           done clear
  D)
              \[2.0\times {{10}^{5}}A{{m}^{-1}}\] done clear
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• question_answer53)
  The relation connecting magnetic susceptibility \[{{\chi }_{m}}\] and relative permeability \[{{\mu }_{r}}\] is:
  A)
  \[{{\chi }_{m}}={{\mu }_{r}}+1\]                    done clear
  B)
              \[{{\chi }_{m}}={{\mu }_{r}}-1\] done clear
  C)
              \[{{\chi }_{m}}=\frac{1}{{{\mu }_{r}}}\]                      done clear
  D)
              \[{{\chi }_{m}}=3(1+{{\mu }_{r}})\] done clear
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• question_answer54)
  The relative permeability of iron is 6200. Its magnetic susceptibility is:
  A)
  6099                             done clear
  B)
              6201      done clear
  C)
              6199                             done clear
  D)
              \[6200\times {{10}^{7}}\]             done clear
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