# MCQ of Magnetism and Matter | Chapter 5 | Physics | Class 12 | CBSE |

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MCQ of Magnetism and Matter, Chapter 5, Physics, Class 12

Question 1 : Pick out the origin of magnetic field

1. Intrinsic spin of electrons and electric Current
2. Polarity of molecules
3. Pauli’s exclusion principle
4. Electronegativity of materials

Answer : A ( Intrinsic spin of electrons and electric Current )

Question 2 : Which of the following statements is incorrect about the magnetic field lines

1. The magnetic lines of force form continuous closed loops
2. By drawing a tangent to magnetic field lines , we can get the direction of net magnetic field
3. As the number of magnetic field lines increases , magnetic force also increases and vice versa .
4. The magnetic lines of force meet each other at certain points.

Answer : D ( The magnetic lines of force intersect each other at certain points. )

Question 3 : Which of the following is true about magnetic monopole ?

1. Monopole of magnet exists
2. Monopole of magnet does not exists .
3. Momentum is constant for magnetic monopole.
4. Momentum varies in case of magnetic monopole as the distance from the field increases.

Answer : B ( Monopole of magnet does not exists .)

Question 4 : A long solenoid having a magnetic moment ‘M’ which corresponds to bar magnet is

1. Magnetic dipole moment will be Equal for both bar magnet and solenoid
2. More magnetic moment for solenoid
3. More magnetic moment for bar magnet
4. None of these

Answer : A ( Equal for both )

Question 5 : Which of the following statements is correct about B.E and B.A?

(B.E represents equatorial magnetic field and B.A refers to axial magnetic field due to bar magnet . )

1. B.E = 2 B.A
2. B.A = 2 B.E
3. B.E = 4 B.A
4. B.A = 4 B.E

Answer : B ( B.A = 2 B.E )

Question 6 : Magnetic moment of a short bar magnet is 0.48 JT-1 . Select the magnitude and direction of magnetic field , which is produced by magnet at a distance of 10 cm from the center of magnet on its axis

1. 0.48 × 10 -4 T along north – south direction
2. 0.28 × 10 -4 T along south – north direction
3. 0.28 × 10 -4 T along north – south direction
4. 0.96 × 10 -4 T along south – north direction

Answer : D ( 0.96 × 10 -4 T along south – north direction )

Question 7 : Magnetic moment of a short bar magnet is 0.39 JT-1 . Select the magnitude and direction of magnetic field , which is produced by magnet at a distance of 20 cm from the equatorial line of the magnet

1. 0.049 G along north – south direction
2. 4.95 G along south – north direction
3. 0.0195 G along south – north direction
4. 19.5 G along north – south direction

Answer : A ( 0.049 G along north – south direction )

Question 8 : Identity the unlike pair

1. ‘Hard magnet’ is associated with ‘alnico’
2. ‘Soft magnet’ is associated with ‘ soft iron’
3. ‘ Bar magnet ‘ is associated with ‘ Equivalent solenoid ‘
4. ‘ Electromagnet is associated with ‘ loud speaker ‘

Answer : D ( ‘ Electromagnet is associated with ‘ loud speaker ‘)

Question 9 : Which material is best to be used in making galvanometer ‘s coil .

1. Cu
2. Ni
3. Fe
4. Both A and B

Answer : C ( Fe )

Question : 10 To reduce residual magnetism to zero by applying magnetizing field in opposite direction is known as :

1. Retentivity
2. Coercivity
3. Hysteresis
4. Flux

Answer : B ( Coercivity )

Question 11 : Earth behaves as a magnet , what is the direction of magnetic field geographically

1. North to south (N-S)
2. South to north (S-N)
3. East to west (E-W)
4. West to east ( W-E)

Answer : B ( South to north(S-N) )

Question 12 : Which of the following entity is not used in specifying earth’s magnetic field ?

1. Magnetic declination
2. Magnetic dip
3. Horizontal component of earth ‘s magnetic field
4. Vertical component of earth ‘ s magnetic field

Answer : D ( Vertical component of earth ‘ s magnetic field )

Question 13 : Which of the following is not a significant difference between electrostatic shielding by a conducting shell and magneto-static shielding ?

1. Electric field lines can terminate on charges and conductors have free charges
2. Magnetic field lines can terminate but conductors can not end them .
3. Magnetic field lines can never terminate on any material and ideal shielding is impossible
4. Highly permeable shells can be used to divert magnetic field lines from the interior region

Answer : B ( Magnetic field lines can terminate but conductors can not end them .)

Question 14 : The earth departs from its dipole shape at a very large distance about an order of 3 × 103 Km. The major factor responsible for this distortion is

1. Motion of ions in the ionosphere
2. Motion of ions in the atmosphere
3. Motion of ions in the lithosphere
4. Motion of ions in the mesosphere

Answer A : (Motion of ions in the ionosphere )

Question 15 : Find the angle of dip at which the horizontal component of earth is merely equal to the vertical component of the Earth’s magnetic field

1. 30°
2. 75°
3. 60°
4. 45°

Answer D : ( 45 ° )

Question 16 : Find the angle of dip at which the vertical component of earth is merely equal to √3 times the horizontal component of the Earth’s magnetic field

1. 30°
2. 75°
3. 60°
4. 45°

Answer C ( 60 ° )

Question 17 : Find the angle of dip at a place where the horizontal component of Earth’s magnetic field is 2 × 10-5 and resultant field is 4 × 10-5 .

1. 30°
2. 60°
3. 90°
4. 45°

Answer : B ( 60 ° )

Question 18 : Some of the substances are given below them maximum magnetic susceptibility ?

1. Calcium
2. Chromium
3. Oxygen
4. Tungsten

Answer : B ( Chromium )

Question 19 : If the temperature of Nickel is increased beyond the Curie temperature then what will happen , given that the liquid shows paramagnetic property at room temperature

1. Anti ferromagnetism will be observed in nickel
2. No magnetic property will be observed in nickel
3. Diamagnetism will be observed in nickel
4. Para – magnetism will be observed in nickel

Answer : D ( Para – magnetism will be observed in nickel )

Question 20 : Pick out the incorrect statement about the magnetic properties of soft iron and steel.

1. Retentivity of soft iron is greater than the retentivity of Steel.
2. Coercivity of soft iron is smaller than coercivity of steel.
3. Area of B-H loop in soft iron is less than the area of B – H loop for steel.
4. Area of B-H loop in soft iron is more than the area of B – H loop for steel.

Answer : D ( Area of B-H loop in soft iron is more than the area of B – H loop for steel.)

Question 21 : What is the value of angles of dip at poles and equator ?

1. Angle of dip at poles is 30° and at equator is 60° .
2. Angle of dip at poles is 0° and at equator is 90° .
3. Angle of dip at poles is 45° and at equator is 90° .
4. Angle of dip at poles is 90° and at equator is 0° .

Answer : D ( Angle of dip at poles is 90° and at equator is 0° )

Question 22 : Find the dipole moment on equator if the equatorial magnetic field of Earth is 0.4 G .

1. Dipole moment on equator is 1.05 × 1023 A m2 .
2. Dipole moment on equator is 2.05 × 1023 A m2 .
3. Dipole moment on equator is 1.05 × 1021 A m2 .
4. Dipole moment on equator is 2.05 × 1021 A m2 .

Answer : A ( Dipole moment on equator is 1.05 × 1023 A m2 . )

Question 23 : The strength of geomagnetic field is
Note :- ( Geomagnetic field is referred to earth’s magnetic field )

1. It remains constant everywhere .
2. It is zero everywhere .
3. It is having a very high value .
4. It vary from place to place on the earth’s surface .

Answer : D ( It vary from place to place on the earth’s surface )

Question 24 : The dipole axis and the axis of earth collectively combine to form a plane ‘S’ . If ‘P’ be the point of intersection of the geographical and the magnetic equator then but will be the angle of declination and the dip angle at point P ?

1. Angle of declination is 0° and angle of dip is 11.3°
2. Angle of declination is 11.3° and angle of dip is 0°
3. Angle of declination is 11.3° and angle of dip is 11.3°
4. Angle of declination is 0° and angle of dip is 0°

Answer : B ( Angle of declination is 11.3° and angle of dip is 0° )

Question 25 : Which of the following is correct expression for the net magnetic flux through any closed surface kept in magnetic field

1. Zero
2. μο/4π
3. 4πμo
4. 4μo/π

Answer : A ( Zero )

Question 26 : The horizontal component of Earth’s magnetic field is is 0.3 G and the vertical component of earth’s magnetic field is 0.52 G then what will be the value of earth’s magnetic field and the angle of dip

1. Earth’s magnetic field is is 0.3 G and angle of dip is 30° .
2. Earth’s magnetic field is is 0.4 G and angle of dip is 40° .
3. Earth’s magnetic field is is 0.5 G and angle of dip is 50° .
4. Earth’s magnetic field is is 0.6 G and angle of dip is 60° .

Answer : D ( Earth’s magnetic field is is 0.6 G and angle of dip is 60° )

Question 27 : Which is the foremost reason responsible for earth’s magnetic field

1. Earth’s magnetic field is due to convective currents in the earth’s core
2. Earth’s magnetic field is due to diversive currents in the earth’s core
3. Earth’s magnetic field is due to rotational motion of earth .
4. Earth magnetic field is due to translational motion of earth .

Answer : A ( Earth’s magnetic field is due to convective currents in the earth’s core )

Question 28 : Which of the following is imprecise statement about the relative magnetic permeability

1. Relative magnetic permeability of a material is dimensionless .
2. Relative magnetic permeability for vacuum medium is one .
3. Relative magnetic permeability for ferromagnetic material is always greater than 1 to large extent.
4. Relative magnetic permeability for paramagnetic material is greater than one .

Answer : D ( Relative magnetic permeability for paramagnetic material is greater than one )

Question 29 : Pick out the correct option which specifies the correct structure for a hysteresis cycle of a transformer core

1. Hysteresis cycle of transformer core is short and wide
2. Hysteresis cycle of transformer core is tall and narrow
3. Hysteresis cycle of transformer core is tall and wide
4. Hysteresis cycle of transformer core is short and narrow

Answer : B ( Hysteresis cycle of transformer core is tall and narrow )

Question 30 : Ramesh is supposed to do an experiment and in that experiment he found that the susceptibility of a given substance is much more greater than one then the substance possibly is

1. Diamagnetic
2. Paramagnetic
3. Ferromagnetic
4. Non – magnetic

Answer : C ( Ferromagnetic )

Question 31 : Let the magnetic field on the earth be carved by that of a point magnetic dipole at the center of the earth then what will be the angle of dip at a point on the geographical equator ?

1. Angle of dip will always be zero
2. Angle of dip can be positive negative or zero
3. Angle of dip is unbounded
4. Angle of dip is always negative

Answer : B ( Angle of dip can be positive negative or zero )

Question 32 : What will be the value of earth’s magnetic field if in the magnetic meridian of a certain place the horizontal component of Earth’s magnetic field is 0.25 G and angle is 60° .

1. 0.50 G
2. 0.52 G
3. 0.54 G
4. 0.56 G

Answer : A ( 0.50 G )

Question 33 : Given a compass needle which is pointing geographical north at a certain place where the horizontal component of earth’s magnetic field is 4 x 10-6 Wb m-2 experiences a torque of 1.2 x 10-3 N m if the magnetic moment of the compass needle is 60 A m2 then what will be the declination of the place

1. 20°
2. 45°
3. 60°
4. 30°

Answer : D ( 30° )

Question 34 : What will be the value of magnetic induction at a point 1 Å away from a Proton along with the axis of spin , given that the magnetic moment of the proton is 1.4 x 10– 6 A m2

1. 0.28 m T
2. 28 m T
3. 0.028 m T
4. 2.8 m T

Answer : D ( 2.8 m T )

Question 35 : A magnetic needle has moment of inertia of 7.8 x 10 – 6 kg m2 and has magnetic moment of 5.8 x 10– 2 Am2 if it completes 12 oscillations in 6 seconds then what will be the magnitude of magnetic field ?

1. The magnitude of magnetic field is 0.011 T
2. The magnitude of magnetic field is 0.021 T
3. The magnitude of magnetic field is 0.031 T
4. The magnitude of magnetic field is 0.041 T

Answer : B ( The magnitude of magnetic field is 0.021 T )

Question 36 : The work done in moving a dipole having a magnetic dipole moment of 0.5 Am2 from its most stable condition to most unstable position in a 0.0 9 T in uniform magnetic field is

1. Work done 0.07 J
2. Work done 0.08 J
3. Work done 0.09 J
4. Work done 0.1 J

Answer : C ( Work done 0.09 J )

Question 37 : A wire is placed between the two poles of of bar magnets if small amount of current it in the wire is into the plane of the paper then what will be the direction of the magnetic force on the wire

1. The direction of magnetic force will be upwards
2. The direction of magnetic field will be downwards
3. The direction of magnetic field will be towards right
4. Direction of magnetic field will be towards left

Answer : D ( Direction of magnetic field will be towards left )

Question 38 : Two identical magnetic dipoles are placed at a separation of 2 m with their axis perpendicular to each other in the air if both of the magnetic dipoles are having in magnetic dipole moment of 2 A m2 to then what will be the Magnetic field at the midpoint between the dipoles

1. 4√5 × 10-5 T
2. 2√5 × 10-5 T
3. 4√5 × 10-7 T
4. 2√5 × 10-7 T

Answer : D ( 2√5 × 10-7 T )

Question 39 : A circular loop is placed in magnetic field such that its plane is perpendicular to the external magnetic field of of magnitude 5.0 x 10– 2 . The loop is free to move about when the coil is is turned slightly and when released it oscillates about its stable equilibrium with a frequency of 2 Hz . What will be the moment of inertia of the loop about its axis of rotation , given that the circular loop has a magnetic moment of 0.355 J T

1. 1.13 × 10-1 Kg m2
2. 1.13 × 10-2 Kg m2
3. 1.13 × 10-3 Kg m2
4. 1.13 × 10-4 Kg m2

Answer : D ( 1.13 × 10-4 Kg m2 )

Question 40 : A magnetizing field produces a magnetic flux density of 8 π T in an iron rod . What will be the relative magnetic permeability of the rod if the magnitude of magnetizing field is 2×103 A m -1 .

1. 102
2. 1
3. 104
4. 103

Answer : C ( 104 )

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