# Moving Charges and Magnetism MCQ Class 12 Physics

Please refer to Chapter 4 Moving Charges and Magnetism MCQ Class 12 Physics with answers below. These multiple-choice questions have been prepared based on the latest NCERT book for Class 12 Physics. Students should refer to MCQ Questions for Class 12 Physics with Answers to score more marks in Grade 12 Physics exams. Students should read the chapter Moving Charges and Magnetism and then attempt the following objective questions.

## MCQ Questions Class 12 Physics Chapter 4 Moving Charges and Magnetism

The Moving Charges and Magnetism MCQ Class 12 Physics provided below covers all important topics given in this chapter. These MCQs will help you to properly prepare for exams.

Question. A positive charge enters in a magnetic field and travels parallel to but opposite the field. If experiences
(a) an upward force.
(b) a downward force.
(c) an accelerated force.
(d) no force.

C

Question. A strong magnetic field is applied on a stationary electron. Then the electron
(a) moves in the direction of the field.
(b) remained stationary.
(c) moves perpendicular to the direction of the field.
(d) moves opposite to the direction of the field.

B

Question. Two a-particles have the ratio of their velocities as 3 : 2 on entering the field. If they move in different circular paths, then the ratio of the radii of their paths is
(a) 2 : 3
(b) 3 : 2
(c) 9 : 4
(d) 4 : 9

B

Question. The nature of parallel and anti-parallel currents are
(a) parallel currents repel and antiparallel cur¬rents attract.
(b) parallel currents attract and antiparallel cur-rents repel.
(c) both currents attract. ’
(d) both currents repel.

B

Question. A charged particle is moving on circular path with velocity v in a uniform magnetic field B, if the velocity of the charged particle is doubled and strength of magnetic field is halved, then radius becomes
(a) 8 times
(b) 4 times
(c) 2 times
(d) 16 times

B

Question. The conversion of a moving coil galvanometer into a voltmeter is done by
(a) introducing a resistance of large value in series.
(b) introducing a resistance of small value in parallel.
(c) introducing a resistance of large value in parallel.
(d) introducing a resistance of small value in series.

A

Question. If a charged particle moves through a magnetic field perpendicular to it
(a) both momentum and energy of particle change.
(b) momentum as well as energy are constant.
(c) energy is constant but momentum changes.
(d) momentum is constant but energy changes.

C

Question. A current carrying closed loop of an irregular shape lying in more than one plane when placed in uniform magnetic field, the force acting on it
(a) will be more in the plane where its larger position is covered.
(b) is zero.
(c) is infinite.
(d) may or may not be zero.

B

Question. The gyro-magnetic ratio of an electron in an H-atom, according to Bohr model, is
(a) independent of which orbit it is in.
(b) neutral
(c) positive
(d) increases with the quantum number n.

A

Question. A current carrying loop is placed in a uniform magnetic field. The torque acting on it does not depend upon
(a) area of loop
(b) value of current
(c) magnetic field
(d) None of these

D

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 dee.
(d) slows down within a dee and speeds up between dees.

A

Question. The nature of parallel and anti-parallel currents are
(a) parallel currents repel and antiparallel cur¬rents attract.
(b) parallel currents attract and antiparallel cur-rents repel.
(c) both currents attract. ’
(d) both currents repel.

B

Question. A current loop placed in a non-uniform magnetic field experiences
(a) a force of repulsion.
(b) a force of attraction.
(c) a torque but not force.
(d) a force and a torque.

D

Question. Which one of the following is correct statement about magnetic forces?
(a) Magnetic forces always obey Newton’s third law.
(b) Magnetic forces do not obey Newton’s third law.
(c) For very high current, magnetic forces obey Newton’s third law.
(d) Inside low magnetic field, magnetic forces obey Newton’s third law.

B

Question. The sensitivity of a tangent galvanometer can be increased by increasing:
(a) the radius of the coil
(b) the external magnetic field
(c) the number of turns of the coil
(d) all the above

B

Question. The conversion of a moving coil galvanometer into a voltmeter is done by
(a) introducing a resistance of large value in series.
(b) introducing a resistance of small value in parallel.
(c) introducing a resistance of large value in parallel.
(d) introducing a resistance of small value in series.

A

Question. The gyro-magnetic ratio of an electron in an H-atom, according to Bohr model, is
(a) independent of which orbit it is in.
(b) neutral
(c) positive
(d) increases with the quantum number n.

A

Question. A current carrying power line carries current from west to east. Then the direction of the magnetic field 2 m above it is :
(a) west to east
(b) south to north
(c) north to south
(d) None of these

C

Question. Two solenoids having lengths L and 2L and the number of loops N and 4N, both have the same current, then the ratio of the magnetic field will be
(a) 1 : 2
(b) 2 : 1
(c) 1 : 4
(d) 4 : 1

A

Question. The sensitivity of a tangent galvanometer can be increased by increasing:
(a) the radius of the coil
(b) the external magnetic field
(c) the number of turns of the coil
(d) all the above

B

Question. A charged particle is moving on circular path with velocity v in a uniform magnetic field B, if the velocity of the charged particle is doubled and strength of magnetic field is halved, then radius becomes
(a) 8 times
(b) 4 times
(c) 2 times
(d) 16 times

B

Question. direction of magnetic force on a positive charge moving in a magnetic field is given by
(a) thumb rule
(b) left hand rule
(c) two hand rule
(d) right hand rule

D

Question. cyclotron is used to
(a) decelerate charged particles or ions to high voltages
(b) accelerate charged particles or ions to high energies
(c) accelerate charged particles or ions to low voltages
(d) accelerate charged particles or ions to high voltages

B

Question. If a current I is flowing in a staight wire parallel to x axis and magnetic field is there in the y axis then
(a) The wire experiences force in x direction
(b) The wire experiences force in y direction
(c) The wire experiences no force
(d) The wire experiences force in z direction

D

Question. A bar magnet is equivalent to
(a) solenoid carrying current
(b) toroid carrying current
(c) circular coil carrying current
(d) straight conductor carrying current

A

Question. The primary origin of magnetism lies in
(a) atomic current and intrinsic spin of electrons.
(b) polar and non polar nature of molecules.
(c) pauli exclusion principle.
(d) electronegative nature of materials.

A

Question. Tangent law is applicable only when:
(a) two uniform and mutually perpendicular magnetic fields exist
(b) two magnetic fields exist
(c) horizontal component of earth’s magnetic field is present
(d) uniform magnetic field are used

A

Question. A magnetic dipole moment is a vector quantity directed from:
(a) S to N
(b) N to S
(c) E to W
(d) W to E

A

Question. A DC current produces a/an:
(a) Magnetic field.
(b) Electric field.
(c) Gravitational field.
(d) Electromagnetic field.
(e) None from the above.

A

Question. A magnet attracts:
(a) Plastics
(b) Any metal
(c) Aluminium
(d) Iron and steel

D

Question. The materials having low retentivity are suitable for making
(a) weak magnets
(b) temporary magnets
(c) permanent magnets
(d) none of the above

B

Question. A magnetic field exerts no force on:
(a) An electric charge moving perpendicular to its direction
(b) An unmagnetised iron bar
(c) A stationary electric charge
(d) A magnet

C

Question. What is the magneto-motive force (mmf) of a wire with 8 turns carrying three amperes of current?
(a) 2,400 At
(b) 240 At
(c) 24 At
(d) 2.4 At

C

Question. A magnetic field exists around
(a) iron
(b) copper
(c) aluminium
(d) moving charges

D

Question. The most effective and quickest may of making a magnet from soft iron is by
(a) placing it inside a coil carrying current
(b) induction
(c) the use of permanent magnet
(d) rubbing with another magnet

A

Question. A permanent magnet
(a) attracts some substances and repels others
(b) attracts all paramagnetic substances and repels others
(c) attracts only ferromagnetic substances
(d) attracts ferromagnetic substances and repels all others

A

Question. The stray line of magnetic flux is defined as
(a) a line vertical to the flux lines
(b) the mean length of a ring shaped coil
(c) a line of magnetic flux in a non-uniform field
(d) a line of magnetic flux which does not follow the designed path

D

Question. The relative permeability is less than unity is case of
(a) ferromagnetic materials
(b) ferrites
(c) non-ferrous materials
(d) diamagnetic materials

D

Question. The magnetic reluctance of a material
(a) decreases with increasing cross sectional area of material
(b) increases with increasing cross-sec-tional area of material
(c) does not vary with increasing cross-sectional area of material
(d) any of the above

A

Question. Paramagnetic materials have relative permeability
(a) slightly less than unity
(b) equal to unity
(c) slightly more than unity
(d) equal to that ferromagnetic mate rials

C

Question. A material which is slightly repelled by a magnetic field is known as
(a) ferromagnetic material
(b) diamagnetic material
(c) paramagnetic material
(d) conducting material

B

Question. For a given wire-wound core, an increase in current through the coil
(a) Reverses the flux lines
(b) Decreases the flux density
(c) Increases the flux density
(d) Causes no change in flux density

C

Question. Magnetising steel is normals difficult because
(a) it corrodes easily
(b) it has high permeability
(c) it has high specific gravity
(d) it has low permeability

D

Question. One telsa is equal to
(a) 1 Wb/mm²
(b) 1 Wb/m
(c) 1 Wb/m²
(d) 1 mWb/m²

C

Question. Which of the following is a ferromagnetic material?
(a) Tungsten
(b) Aluminium
(c) Copper
(d) Nickel

D

Question. An electron moving with kinetic energy 6×10–16 joules enters a field of magnetic induction 6 × 10–3 weber/m2 at right angle to its motion. The radius of its path is
(a) 3.42 cm
(b) 4.23 cm
(c) 5.17 cm
(d) 7.7 cm

A

Question. A charged particle with velocity 2 × 103 m/s passes undeflected through electric and magnetic field. Magnetic field is 1.5 tesla. The electric field intensity would be
(a) 2 × 103 N/C
(b) 1.5 × 103 N/C
(c) 3 × 103 N/C
(d) 4/3 × 10–3 N/C

C

Question. A current carrying conductor placed in a magnetic field experiences maximum force when angle between current and magnetic field is
(a) 3 π/4
(b) π/2
(c) π/4
(d) zero

C

Question. If in a circular coil A of radius R, current I is flowing and in another coil B of radius 2R a current 2I is flowing, then the ratio of the magnetic fields BA and BB, produced by them will be
(a) 1
(b) 2
(c) 1/2
(d) 4

A

Question. An electron moves in a circular arc of radius 10 m at a contant speed of 2 × 107 ms–1 with its plane of motion normal to a magnetic flux density of 10–5 T. What will be the value of specific charge of the electron?
(a) 2 × 104 C kg–1
(b) 2 × 105 C kg–1
(c) 5 × 106 C kg–1
(d) 2 × 1011 C kg–1