CUET Physics MCQs Unit III Magnetic Effects of Current and Magnetism

CUET Physics Moving Charges and Magnetism MCQs

Question: Which of the following is true ?
(a) Parallel currents repel, and antiparallel currents attract.
(b) Parallel currents attract, and antiparallel currents repel.
(c) Both parallel and antiparallel currents attract.
(d) Both parallel and antiparallel currents repel.

Answer: B

Question: In cyclotron the resonance condition is
(a) the frequency of revolution of charged particle is equal to the frequency of A.C. voltage sources
(b) the frequency of revolution of charged particle is equal to the frequency of applied magnetic field
(c) the frequency of revolution of charged particle is equal to the frequency of rotation of earth
(d) the frequency of revolution of charged particle, frequency of A.C. source and frequency of magnetic field are equal

Answer: A

Question:  Biot-Savart law indicates that the moving electrons (velocity v) produce a magnetic field B such that
(a) B is perpendicular of
(b) B is parallel to v
(c) it obeys inverse cube law
(d) it is along the line joining the electron and point of observationt

Answer: A

Question: A charged particle moving in a uniform magnetic field and losses 4% of its kinetic energy. The radius of curvature of its path changes by
(a) 2%
(b) 4%
(c) 10%
(d) 12%

Answer: C

Question: Biot-Savart law indicates that the moving electrons velocity (V) produce a magnetic field B such that
(a) B ∥ V
(b) B ⊥ V
(c) it obeys inverse cube law
(d) it is along the line joining electron and point of observation

Answer: B

Question: Magnetic field at the centre of a circular coil of radius r, through which a current I flows is
(a) directly proportional to r
(b) inverseley proportional to I
(c) directly proportional to I
(d) directly proprotional to I2 

Answer: C

Question: A moving coil galvanometer has N number of turns in a coil of effective area A, it carries a current I. The magnetic field B is radial. The torque acting on the coil is
(a) NA2B2I
(b) NABI2
(c) N2ABI 
(d) NABI

Answer: D

Question: An electric charge in uniform motion produces
(a) an electric field only
(b) a magnetic field only
(c) both electric and magnetic fields
(d) no such field at all

Answer: C

Question: A wire is placed parallel to the lines of force in a magnetic field and a current flows in the wire. Then
(a) the wire will experience a force in the direction of the magnetic field
(b) the wire will not experience any force at all
(c) the wire will experience a force in a direction opposite to the field
(d) it experiences a force in a direction perpendicular to lines of force

Answer: B

Question: Consider a moving charged particle in a region of magnetic field. Which of the following statements are correct ?
I. If v is parallel to B, then path of particle is spiral.
II. If v is perpendicular to B, then path of particle is a circle.
III. If v has a component along B, then path of particle is helical.
IV. If v is along B, then path of particle is a circle.
(a) I and II 
(b) II and III
(c) III and IV
(d) IV and I

Answer: B

Question: A particle of mass m and charge q enters a magnetic field B perpendicularly with a velocity v. The radius of the circular path described by it will be
(a) Bq / mv
(b) mq / Bv
(c) mB / qv 
(d) mv / Bq

Answer: D

Question: Magnetic dipole moment of a rectangular loop is
(a) inversely proportional to current in loop
(b) inversely proportional to area of loop
(c) parallel to plane of loop and porportional to area of loop
(d) perpendicular to plane of loop and porportional to area of loop

Answer: D

Question: The deflection in a moving coil galvanometer is
(a) directly proportional to the torsional constant
(b) directly proportional to the number of turns in the coil
(c) inversely proportional to the area of the coil
(d) inversely proportional to the current flowing

Answer: B

Question: A metallic rod of mass per unit length 0.5 kg m–1 is lying horizontally on a smooth inclined plane which makes an angle of 30°with the horizontal. The rod is not allowed to slide down by flowing a current through it when a magnetic field of induction 0.25 T is acting on it in the vertical direction. The current flowing in the rod to keep it stationary is
(a) 7.14 A
(b) 5.98 A
(c) 11.32 A
(d) 14.76 A

Answer: C

Question: The deflection in a moving coil galvanometer is
(a) directly proportional to the torsional constant
(b) directly proportional to the number of turns in the coil
(c) inversely proportional to the area of the coil
(d) inversely proportional to the current flowing

Answer: B

Question:  An electron is projected with uniform velocity along the axis of a current carrying long solenoid. Which of the following is true?
(a) The electron will be accelerated along the axis
(b) The electron path will be circular about the axis
(c) The electron will experience a force at 45° to the axis and hence execute a helical path
(d) The electron will continue to move with uniform velocity along the axis of the solenoid

Answer: D

Question: Two particles X and Y having equal charges, after being accelerated through the same potential difference, enter a region of uniform magnetic field and describe circular paths of radii R1 and R2, respectively. The ratio of masses of X
(a) (R1/R2)1/2
(b) (R2/R1)
(c) (R1/R2)2
(d) (R1/R2)

Answer: C

Question: Similarities of Biot–Savart’s law and Coulomb’s law for the electrostatics are
I. both are long range and inversely proportional to the square of distance from the source to the point of interest.
II. both are linear in source.
III. both are produced by scalar sources.
IV. both follow principle of superposition.
(a) I, II and III
(b) II, III and IV
(c) I, II and IV 
(d) I, III and IV

Answer: C

Question: If a copper rod carries a direct current, the magnetic field associated with the current will be
(a) only inside the rod
(b) only outside the rod
(c) both inside and outside the rod
(d) neither inside nor outside the rod

Answer: C

Question: Lorentz force is
(a) electrostatic force acting on a charged particle.
(b) magnetic force acting on a moving charged particle.
(c) the vector sum of electrostatic and magnetic force acting on a moving charged particle.
(d) the vector sum of gravitational and magnetic force acting on a moving charged particle.

Answer: C

Question: Energy in a current carrying coil is stored in the form of
(a) electric field 
(b) magnetic field
(c) dielectric strength
(d) heat

Answer: B

Question: A charged particle moves through a magnetic field in a direction perpendicular to it. Then the
(a) velocity remains unchanged
(b) speed of the particle remains unchanged
(c) direction of the particle remains unchanged
(d) acceleration remains unchanged

Answer: B

Question: A charge q is moving with a velocity v parallel to a magnetic field B. Force on the charge due to magnetic field is
(a) q v B
(b) q B/v
(c) zero 
(d) B v/q

Answer: C

Question: The magnetic moment of a circular coil carrying current is
(a) directly proportional to the length of the wire in the coil
(b) inversely proportional to the length of the wire in the coil
(c) directly proportional to the square of the length of the wire in the coil
(d) inversely proportional to the square of the length of the wire in the coil

Answer: C

Question: A coil of circular cross-section having 1000 turns and 4 cm² face area is placed with its axis parallel to a magnetic field which decreases by 10^–2 Wb m^–2 in 0.01 s. The e.m.f. induced in the coil is:
(a) 400 mV
(b) 200 mV
(c) 4 mV    
(d) 0.4 mV

Answer: A

Question: The AC voltage across a resistance can be measured using a

(a) hot wire voltmeter
(b) moving coil galvanometer
(c) potential coil galvanometer
(d) moving magnet galvanometer

Answer: B

Question:  In a cyclotron, a charged particle
(a) undergoes acceleration all the time
(b) speeds up between the dees because of the magnetic field
(c) speeds up in a dees
(d) slows down within a dee and speeds up between dees

Answer: A

Question: A deuteron of kinetic energy 50 keV is describing a circular orbit of radius 0.5 metre in a plane perpendicular to the magnetic field B. The kinetic energy of the proton that describes a circular orbit of radius 0.5 metre in the same plane with the same B is
(a) 25 keV
(b) 50 keV
(c) 200 keV
(d) 100 keV

Answer: D

Question: Magnetic field inside a solenoid is
(a) directly proportional to its length
(b) directly proportional to current
(c) inversely proportional to total number of turns
(d) inversely porportional to current

Answer: B

Question: Which of the following is the correct definition of ampere?
(a) The ampere is the value of that steady current which when maintained in each of the two very long, straight, parallel conductors of negligible cross-section, and placed one metre apart in vacuum, would produce on each of these conductors a force equal to 2 × 107 N/m of length. 
(b) The ampere is the value of that steady current which when maintained in each of the two very long, straight, parallel conductors of negligible cross-section, and placed one centimetre apart in vacuum, would produce on each of these conductors a force equal to 2 × 10–7 N/m of length. 
(c) The ampere is the value of that steady current which, when maintained in each of the two very long, straight, parallel conductors of negligible cross-section, and placed one metre apart in vacuum, would produce on each of these conductors a force equal to 2 × 10–7 N/m of length.
(d) The ampere is the value of that steady current which, when maintained in each of the two very long, straight, parallel conductors of negligible cross-section, and placed ten metre apart in vacuum, would produce on each of these conductors a force equal to 2 × 10–7 N/m of length.

Answer: C

Question: A current carrying loop is placed in a uniform magnetic field. The torque acting on it does not depend upon
(a) shape of the loop 
(b) area ot the loop
(c) value of the current
(d) magnetic field

Answer: A

Question: Consider the following statements and select the incorrect statement(s).
I. The presence of a large magnetic flux through a coil maintains a current in the coil if the circuit is continuous
II. A coil of a metal wire kept stationary in a non– uniform magnetic field has an e.m.f induced in it
III. A charged particle enters a region of uniform magnetic field at an angle of 85° to the magnetic lines of force, the path of the particle is a circle
IV. There is no change in the energy of a charged particle moving in a magnetic field although a magnetic force is acting on it
(a) I and II
(b) II and III
(c) II only 
(d) IV only

Answer: D

Question: A milli voltmeter of 25 milli volt range is to be converted into an ammeter of 25 ampere range. The value (in ohm) of necessary shunt will be
(a) 0.001
(b) 0.01
(c) 1
(d) 0.05

Answer: A

Question: A current carrying circular loop of radius R is placed in the x-y plane with centre at the origin. Half of the loop with x > 0 is now bent so that it now lies in the y-z plane.
(a) The magnitude of magnetic moment now diminishes
(b) The magnetic moment does not change
(c) The magnitude of B at (0, 0, z), z > R increases
(d) The magnitude of B at (0, 0, z), z >> R is unchanged

Answer: A

Question: Choose the correct option
Assertion : Free electrons always keep on moving in a conductor even then no magnetic force act on them in magnetic field unless a current is passed through it.
Reason : The average velocity of free electron is zero.
(a) Assertion is correct, reason is correct; reason is a correct explanation for assertion.
(b) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
(c) Assertion is correct, reason is incorrect
(d) Assertion is incorrect, reason is correct.

Answer: B

Question: Two parallel circular coils of equal radii having equal number of turns placed coaxially and separated by a distance equal to the radii of the coils carrying equal currents in same direction are known as
(a) Biot-savart’s coils
(b) Ampere’s coils
(c) Helmholtz coils 
(d) Oersted’s coils.

Answer: C

Question: If a long hollow copper pipe carries a direct current, the magnetic field associated with the current will be
(a) only inside the pipe
(b) only outside the pipe
(c) neither inside nor outside the pipe
(d) both inside and outside the pipe

Answer: B

Question: Direction of force due to magnetic field on a moving charged particle is
I. perpendicular to direction of velocity of charged particle.
II. perpendicular to direction of magnetic field.
III. parallel to direction of velocity of charged particle.
IV. parallel to the direction of magnetic field.
Correct statements are
(a) I and IV 
(b) I and II
(c) I and III
(d) III and IV

Answer: B

Question: In a moving coil galvanometer, the deflection of the coil θ is related to the elecrical current i by the relation
(a) i ∝ tan θ 
(b) i ∝θ
(c) i ∝ θ2
 (d) i ∝ θ 

Answer: B

Question:  The current sensitivity of a galvanometer is defined as
(a) the current flowing through the galvanometer when a unit voltage is applied across its terminals.
(b) current per unit deflection.
(c) deflection per unit current.
(d) dflection per unit current when a unit voltage is applied across its terminals

Answer: C

Question:  A proton and an alpha particle both enter a region of uniform magnetic field B, moving at right angles to field B. If the radius of circular orbits for both the particles is equal and the kinetic energy acquired by proton is 1 MeV the energy acquired by the alpha particle will be:
(a) 0.5 MeV
(b) 1.5 MeV
(c) 1 MeV   
(d) 4 MeV

Answer: C

Question: Ampere’s circuital law is equivalent to
(a) Biot-Savart law 
(b) Coulomb’s law
(c) Faraday’s law
(d) Kirchhoff’s law

Answer: A

Question: If a current is passed through a spring then the spring will
(a) expand 
(b) compress
(c) remains same
(d) None of these

Answer: C

Question: Two parallel wires carrying currents in the same direction attract each other because of
(a) potential difference between them
(b) mutual inductance between them
(c) electric forces between them
(d) magnetic forces between them

Answer: D

Question: The magnetic dipole moment of a current loop is independent of
(a) magnetic field in which it is lying
(b) number of turns
(c) area of the loop
(d) current in the loop'

Answer: A

Question:  A charged particle enters in a uniform magnetic field with a certain velocity. The power delivered to the particle by the magnetic field depends on
(a) force exerted by magnetic field and velocity of the particle.
(b) angular speed w and radius r of the circular path.
(c) angular speed w and acceleration of the particle.
(d) None of these

Answer: D

Question: According to oersted, around a current carrying conductor, magnetic field exists
(a) as long as there is current in the wire
(b) even after removing the current in the wire
(c) only few seconds after removing the current
(d) None of these 

Answer: A

Question: A long solenoid has a radius a and number of turns per unit length n. If it carries a current i, then the magnetic field on its axis is directly proportional to
(a) ani
(b) ni
(c) ni /a
(d) n2i

Answer: B

Question: In cyclotron the gyro radius is
(a) proportional to momentum
(b) proportional to energy
(c) inversely proportional to momentum
(d) inversely proportional to energy

Answer: A

Question: Choose the correct option
Assertion: The frequency of circular motion of a charged particle in cyclotron is independent of the mass of the particle.
Reason: Greater the mass of the particle less will be the frequency of the particle
(a) Assertion is correct, reason is correct; reason is a correct explanation for assertion.
(b) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
(c) Assertion is correct, reason is incorrect
(d) Assertion is incorrect, reason is correct.

Answer: D

Question: The current sensitivity of a galvanometer is defined as
(a) the current flowing through the galvanometer when a unit voltage is applied across its terminals.
(b) current per unit deflection.
(c) deflection per unit current.
(d) dflection per unit current when a unit voltage is applied across its terminals 

Answer: C

Question: Two free parallel wires carrying currents in the opposite directions
(a) attract each other
(b) repel each other
(c) do not attract each other
(d) get rotated to be perpendicular to each other

Answer: B

Question: A charged particle moves through a magnetic field perpendicular to its direction. Then
(a) kinetic energy changes but the momentum is constant
(b) the momentum changes but the kinetic energy is constant
(c) both momentum and kinetic energy of the particle are not constant
(d) both momentum and kinetic energy of the particle are constant

Answer: B

Question: The magnetic field around a long straight current carrying wire is
(a) spherical symmetry 
(b) cylindrical symmetry
(c) cubical symmetry
(d) unsymmetrical 

Answer: B

Question: Cyclotron is used to accelerate
(a) electrons
(b) neutrons
(c) positive ions 
(d) negative ions

Answer: C

Question: An electron having a charge e moves with a velocity v in X-direction. An electric field acts on it in Y-direction? The force on the electron acts in
(a) positive direction of Y-axis
(b) negative direction of Y-axis
(c) positive direction of Z-axis
(d) negative direction of Z-axis

Answer: B

Question:  The length of a solenoid is 0.4 m and the number turns in it is 500. A current of 3 amp, is flowing in it. In a small coil of radius 0.01 m and number of turns 10, a current of 0.4 amp. is flowing. The torque necessary to keep the axis of this coil perpendicular to the axis of solenoid will be
(a) 5.92 × 10^–6 N-m       
(b) 5.92 × 10^–4 N-m
(c) 5.92 × 10^–6 dyne-cm
(d) 5.92 × 10^–4 dyne-cm

Answer: A

Question: Ampere’s circuital law states that
(a) the surface integral of magnetic field over the open surface is equal to μ0 times the total current passing through the surface.
(b) the surface integral of magnetic field over the open surface is equal to μ0 times the total current passing near the surface.
(c) the line integral of magnetic field along the boundary of the open surface is equal to μ0 times the total current passing near the surface.
(d) the line integral of magnetic field along the boundary of the open surface is equal to μ0 times the total current passing through the surface.

Answer: D

Question: To make the field radial in a moving coil galvanometer
(a) the number of turns in the coil is increased
(b) magnet is taken in the form of horse-shoe
(c) poles are cylindrically cut
(d) coil is wounded on aluminium frame

Answer: C
 

CUET Physics Magnetism and Matter MCQs

Question: The ratio of magnetic fields due to a smaller bar magnet in the end on position to broad side on position is
(a) 1/4
(b) 1/2
(c) 1 
(d) 2

Answer: D

Question: The earth’s magnetic field always has a vertical component except at the
(a) magnetic equator 
(b) magnetic poles
(c) geographic north pole
(d) latitude 45º

Answer: A

Question: Hysterisis is the phenomenon of lagging of
(a) I behind B
(b) B behind I
(c) I and B behind H
(d) H behind I

Answer: C

Question: 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° with the axis of the earth. At Mumbai, declination is nearly zero. Then,
(a) the declination varies between 11.3° W to 11.3° E
(b) the least declination is 0°
(c) the plane defined by dipole axis and the earth axis passes through Greenwich
(d) declination averaged over the earth must be always negative

Answer: A

Question: The coercivity of a small magnet where the ferromagnet gets demagnetized is 3 × 10³ Am^–1. The current required to be passed in a solenoid of length 10 cm and number of turns 100, so that the magnet gets demagnetized when inside the solenoid, is
(a) 30 mA
(b) 60 mA
(c) 3 A
(d) 6 A

Answer: C

Question: A magnetic needle of magnetic moment 6.7 × 10^–2 Am² and moment of inertia 7.5 × 10^–6 kg m² is performing simple harmonic oscillations in a magnetic field of 0.01 T. Time taken for 10 complete oscillations is :
(a) 6.98 s
(b) 8.76 s
(c) 6.65 s
(d) 8. 89 s

Answer: C

Question: Current I is flowing in a coil of area A and number of turns is N, then magnetic moment of the coil in M equal to
(a) NIA 
(b) NI/A
(c) NI/ A
(d) N2 AI

Answer: A

Question: A circular loop carrying a current is replaced by an equivalent magnetic dipole. A point on the axis of the loop is in
(a) end-on position 
(b) broadside-on position
(c) both
(d) None of these 

Answer: A

Question: On cutting a solenoid in half, the field lines remain ...A...,emerging from one face of the solenoid and entering into the other face. Here, A refers to
(a) irregular
(b) discontinuous
(c) continuous 
(d) alternate

Answer: C

Question: At magnetic poles, the angle of dip is
(a) 45º
(b) 30º
(c) zero
(d) 90º

Answer: D

Question: The magnetic compass is not useful for navigation near the magnetic poles, since
(a) R = 0
(b) V = 0
(c) H = 0
(d) θ = 0º

Answer: C

Question: One can define ...A... of a place as the vertical plane which passes through the imaginary line joining the magnetic North and the South–poles. Here, A refers to
(a) geographic meridian
(b) magnetic meridian
(c) magnetic declination
(d) magnetic inclination

Answer: B

Question: If μ0 is absolute permeability of vacuum and μr is relative magnetic permeability of another medium, then permeability μ of the medium is
(a) μ0 μr
(b) μ0/μr
(c) μr/μ0
(d) 1/μ0 μR

Answer: D

Question: The magnetic susceptibility for diamagnetic materials is
(a) small and negative
(b) small and positive
(c) large and positive
(d) large and negative

Answer: A

Question: The narrowest hysterisis loop is for
(a) cobalt steel
(b) alnico
(c) perm alloy
(d) stainless steel

Answer: C

Question: A diamagnetic material in a magnetic field moves
(a) perpendicular to field
(b) from stronger to weaker parts of field
(c) from weaker to stronger parts of the field
(d) None of these

Answer: B

Question: Which of the following is the most suitable material for making permanent magnet ?
(a) Steel
(b) Soft iron
(c) Copper
(d) Nickel

Answer: A

Question: Choose the correct option
Assertion : The poles of magnet can not be separated by breaking into two pieces.
Reason : The magnetic moment will be reduced to half when a magnet is broken into two equal pieces
(a) Assertion is correct, reason is correct; reason is a correct explanation for assertion.
(b) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
(c) Assertion is correct, reason is incorrect
(d) Assertion is incorrect, reason is correct.

Answer: B

Question: Choose the correct option
Assertion : The earth¢s magnetic field is due to iron present in its core.
Reason : At a high temperature magnet losses its magnetism
(a) Assertion is correct, reason is correct; reason is a correct explanation for assertion.
(b) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
(c) Assertion is correct, reason is incorrect
(d) Assertion is incorrect, reason is correct

Answer: D

Question: A long straight horizontal cable carries a current of 2.5 A in the direction 10° south of west to 10° north of east. The magnetic meridian of the place happens to be 10° west of the geographic meridian. The earth’s magnetic field at the location is 0.33 Gauss, and the angle of dip is zero. Locate the line of neutral points. (Ignore the thickness of the cable).
(a) 1.5 cm
(b) 2.5 cm
(c) 3.5 cm
(d) 2.0 cm

Answer: A

Question: The strength of the earth’s magnetic field is
(a) constant everywhere
(b) zero everywhere
(c) having very high value
(d) vary from place to place on the earths surface

Answer: D

Question: Susceptibility is positive and large for a
(a) paramagnetic substance
(b) ferromagnetic substance
(c) diamagnetic substance
(d) non magnetic substance

Answer: B

Question: Metals getting magnetised by orientation of atomic magnetic moments in external magnetic field are called
(a) diamagnetic
(b) paramagnetic
(c) ferromagnetic
(d) antimagnetic

Answer: B

Question: The hysterisis curve is studied generally for
(a) ferromagnetic materials
(b) paramagnetic materials
(c) diamagnetic materials
(d) all of the above 

Answer: A

Question: The hysteresis cycle for the material of permanent magnet is
(a) short and wide
(b) tall and narrow
(c) tall and wide 
(d) short and narrow

Answer: C

Question: A thin diamagnetic rod is placed vertically between the poles of an electromagnet. When the current in the electromagnet is switched on, then the diamagnetic rod is pushed up, out of the horizontal magnetic field. Hence the rod gains gravitational potential energy. The work required to do this comes from
(a) the current source
(b) the magnetic field
(c) the induced electric field due to the changing magnetic field
(d) the lattice structure of the material of the rod

Answer: A

Question: A very small magnet is placed in the magnetic meridian with its south pole pointing north. The null point is obtained 20 cm away from the centre of the magnet. If the earth¢s magnetic field (horizontal component) at this point be 0.3 gauss, the magnetic moment of the magnet is
(a) 8.0 × 102 e.m.u.
(b) 1.2 × 103 e.m.u.
(c) 2.4 × 103 e.m.u.
(d) 3.6 × 103 e.m.u.

Answer: B

Question: Choose the correct option
Assertion : The ferromagnetic substance do not obey Curie’s law.
Reason : At Curie point a ferromagnetic substance start behaving as a paramagnetic substance.
(a) Assertion is correct, reason is correct; reason is a correct explanation for assertion.
(b) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
(c) Assertion is correct, reason is incorrect
(d) Assertion is incorrect, reason is correct.

Answer: C

Question: Choose the correct option
Assertion : Electromagnetic are made of soft iron.
Reason : Coercivity of soft iron is small.
(a) Assertion is correct, reason is correct; reason is a correct explanation for assertion.
(b) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
(c) Assertion is correct, reason is incorrect
(d) Assertion is incorrect, reason is correct.

Answer: B

Question: A bar magnet is cut into two equal halves by a plane parallel to the magnetic axis. Of the following physical quantities the one which remains unchanged is
(a) pole strength
(b) magnetic moment
(c) intensity of magnetisation
(d) None of these

Answer: C

Question: The magnetic lines of force inside a bar magnet
(a) are from N-pole to S-pole of magnet
(b) do not exist
(c) depend upon the area of cross section of bar magnet
(d) are from S-pole of magnet

Answer: D

Question: The magnetic moment of a bar magnet is thus ...A... to the magnetic moment of an equivalent solenoid that produces the same magnetic field.
Here, A refers to
(a) unequal
(b) different
(c) equal 
(d) same

Answer: C

Question: A compass needle which is allowed to move in a horizontal plane is taken to a geomagnetic pole. It will
(a) stay in north-south direction only
(b) stay in east-west direction only
(c) become rigid showing no movement
(d) stay in any position

Answer: D

Question: When the temperature of a magnetic material decreases, the magnetization
(a) decreases in a diamagnetic material
(b) decreases in a paramagnetic material
(c) decreases in a ferromagnetic material
(d) remains the same in a diamagnetic material

Answer: D

Question: If a diamagnetic substance is brought near north or south pole of a bar magnet, it is
(a) attracted by poles
(b) repelled by poles
(c) replaced by north pole and attracted by south pole
(d) attracted by north pole and repelled by south pole

Answer: B

Question: A temporary magnet is made of
(a) cast iron
(b) steel
(c) soft iron
(d) stainless steel

Answer: A

Question: The given figure represents a material which is
(a) paramagnetic
(b) diamagnetic
(c) ferromagnetic
(d) none of these

Answer: B

Question: The time period of oscillation of a magnet in a vibration magnetometer is 1.5 sec. The time period of oscillation of another magnet similar in size, shape and mass but having 1/4 magnetic moment than that of the 1st magnet oscillating at the same place will be
(a) 0.75 sec
(b) 1.5 sec
(c) 3.0 sec
(d) 6.0 sec

Answer: C

Question: Magnetic lines of force due to a bar magnet do not intersect because
(a) a point always has a single net magnetic field
(b) the lines have similar charges and so repel each other
(c) the lines always diverge from a single force
(d) the lines need magnetic lenses to be made to interest

Answer: A

Question: Two points A and B are situated at a distance x and 2x respectively from the nearer pole of a magnet 2 cm long. The ratio of magnetic field at A and B is
(a) 4 : 1 exactly           
(b) 4 : 1 approximately
(c) 8 : 1 approximately
(d) 1 : 1 approximately

Answer: C

Question: Demagnetisation of magnets can be done by
(a) rough handling
(b) heating
(c) magnetising in the opposite direction
(d) All of the above

Answer: D

Question: Magnetic lines of force due to a bar magnet do not intersect because
(a) a point always has a single net magnetic field
(b) the lines have similar charges and so repel each other
(c) the lines always diverge from a single force
(d) the lines need magnetic lenses to be made to interest

Answer: A

Question: Magnetic field intensity is defined as
(a) Magnetic moment per unit volume
(b) Magnetic induction force acting on a unit magnetic pole
(c) Number of lines of force crossing per unit area
(d) Number of lines of force crossing per unit volume

Answer: B

Question: A dip circle is taken to geomagnetic equator. The needle is allowed to move in a vertical plane perpendicular to the mangetic meridian. the needle will stay in
(a) horizontal direction only
(b) vertical direction only
(c) any direction except vertical and horizontal
(d) any direction it is released

Answer: D

Question: Which of the following is not correct about relative magnetic permeability (μ,)? 
(a) It is a dimensionsless pure ratio.
(b) For vacuum medium its value is one.
(c) For ferromagnetic materials μ, > > 1
(d) For paramagnetic materials μ, > 1.

Answer: D

Question: A material is placed in a magnetic field and it is thrown out of it. Then the material is
(a) paramagnetic
(b) diamagnetic
(c) ferromagnetic
(d) non-magnetic

Answer: B

Question: Permanent magnets are the substances having the property of
(a) ferromagnetism at room temperature for a long period of time.
(b) paramagnetism at room temperature for a long period of time.
(c) anti ferromagnetism at room temperature for a long period of time.
(d) diamagnetism at room temperature for a long period of time. 

Answer: A

Question: A magnetic dipole is under the influence of two magnetic fields The angle between the field directions is 60° and one of the fields has a magnitude of 1.2 × 10–2 T. If the dipole comes to stable equilibrium at an angle of 15° with this field, what is the magnitude of other field ?
(a) 4.4 × 10–3 tesla
(b) 5.2 × 10–3 tesla
(c) 3.4 × 10–3 tesla
(d) 7.8 × 10–3 tesla

Answer: A

Question: Choose the correct option
Assertion : A paramagnetic sample display greater magnetisation (for the same magnetic field) when cooled.
Reason : The magnetisation does not depend on temperature
(a) Assertion is correct, reason is correct; reason is a correct explanation for assertion.
(b) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
(c) Assertion is correct, reason is incorrect
(d) Assertion is incorrect, reason is correct.

Answer: D

Question: Identify the mismatched pair
(a) Hard magnet - Alnico
(b) Soft magnet - Soft iron
(c) Bar magnet - Equivalent solenoid
(d) Permanent magnet - Loud speaker

Answer: D

Question: A diamagnetic material in a magnetic field moves
(a) perpendicular to the field
(b) from stronger to the weaker parts of the field
(c) from weaker to the stronger parts of the field
(d) None of these

Answer: B

Question: Which of the following is responsible for the earth’s magnetic field?
(a) Convective currents in earth’s core.
(b) Diversive current in earth’s core.
(c) Rotational motion of earth.
(d) Translational motion of earth.

Answer: A

Question: Among which of the following the magnetic susceptibility does not depend on the temperature?
(a) Dia-magnetism
(b) Para-magnetism
(c) Ferro-magnetism
(d) Ferrite

Answer: A

Question: A magnetic dipole is acted upon by two magnetic fields which are inclined to each other at an angle of 75°. One of the fields has a magnitude of 15 mT. The dipole attains stable equilibrium at an angle of 30° with this field. The magntidue of the other field (in mT) is close to
(a) 1
(b) 11
(c) 36
(d) 1060

Answer: B

Question: The magnetic susceptibility is negative for
(a) diamagnetic material only
(b) paramagnetic material only
(c) ferromagnetic material only
(d) paramagnetic and ferromagnetic materials

Answer: A

Question: When a current in a circular loop is equivalently replaced by a magnetic dipole
(a) the pole strength m of each pole is fixed
(b) the distance d between the poles is fixed
(c) the product md is fixed
(d) None of these

Answer: C

Question: At the magnetic north pole of the earth, the value of the horizontal component of earth’s magnetic field and angle of dip are respectively
(a) zero, maximum
(b) maximum, minimum
(c) maximum, maximum
(d) minimum, minimum

Answer: A

Question: Curie temperature is the temperature above which
(a) a ferromagnetic material becomes paramagenetic
(b) a paramagnetic material becomes diamagnetic
(c) a ferromagnetic material becomes diamagnetic
(d) a paramagnetic meterial becomes ferromagnetic

Answer: A

Question: A dip circle is so set that its needle moves freely in the magnetic meridian. In this position, the angle of dip is 40º. Now the dip circle is rotated so that the plane in which the needle moves makes an angle of 30º with the magnetic meridian. In this position, the needle will dip by an angle
(a) 40º         
(b) 30º
(c) more than 40º
(d) less than 40º

Answer: B

Question: The magnetism of magnet is due to
(a) pressure of big magnet inside the earth
(b) earth
(c) cosmic rays
(d) the spin motion of electron

Answer: D

Question: The lines of force due to earth’s horizontal magnetic field are
(a) parallel and straight 
(b) concentric circles
(c) elliptical
(d) curved lines

Answer: B

Question: Which magnetic materials have negative susceptibility?
(a) diamagnetic materials
(b) paramagnetic materials
(c) ferromagnetic materials
(d) All the above

Answer: A

Question: Core of elctromagnets are made of ferromagnetic materials which have
(a) low permeability and low retentivity
(b) high permeability and high retentivity
(c) high permeability and high retentivity.
(d) low permeability and high retentivity.

Answer: C 

Question: Magnetic dipole moment is a vector quantity directed from
(a) south pole to north pole
(b) north pole to south pole
(c) east to west
(d) west to east

Answer: A

Question: The ratio of intensity of magnetisation and magnetising field is called
(a) permeability
(b) magnetic intensity
(c) magnetic intensity
(d) magnetic susceptibility

Answer: D

Question: The materials suitable for making electromagnets should have
(a) high retentivity and low coercivity
(b) low retentivity and low coercivity
(c) high retentivity and high coercivity
(d) low retentivity and high coercivity

Answer: B

Question: The primary origin (s) of magnetism lies in
(a) atomic currents
(b) polar nature of molecules
(c) extrinsic spin of electron
(d) None of these

Answer: A

Question: Materials suitable for permanent magnet, must have which of the following properties?
(a) High retentivity, low coercivity and high permeability.
(b) Low retentivity, low coercivity and low permeability.
(c) Low retentivity, high coercivity and low permeability.
(d) High retentivity, high coercivity and high permeability.

Answer: D