Magnetism and matter MCQs class 12
MCQs On Magnetism and matter for NEET pdf
Check your knowledge by solving MCQ on magnetism and matter with answers Pdf. Below MCQs will help learners for preparing NEET examinations and will be able to score better as all the resources required to study of magnetism are provided here. We tried to simplify the complexities of some of the topics in the form of Magnetism and matter multiple choice questions and answers so that preparation becomes easy for the NEET aspirants.
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MCQs Questions On Magnetism and matter Class 12
1. when the current flowing in a circular coil is doubled and the number of turns of the coil in it is halved, the magnetic field at its centre will become_______
(a) Same
(b) Four times
(c) Half
(d) Double
Answer: A
2. Which of the following statement is not true;magnetic field at the centre of current carrying loop?
(a) proportional to current
(b) inversely proportional to radius
(c) proportional to number of turns
(d) none
Answer: D
3. A circular coil of radius R carries an electric current.The magnetic field due the coil at a point on the axis of the coil located at a distance r from the center of the coil, such that r >> R varies as__________
(a) 1/r
(b) 1/r¾
(c) 1/r2
(d) 1/r3
Answer: D
4. Two concentric circular loops of radii 0·08m and 0·1m carries current such that magnetic field at the centre is zero. If the current in the outer loop is 8A clockwise, current in the inner loop is______
(a) 6·4 A anticlockwise
(b) 6·4 A clockwise
(c) 8A anticlockwise
(d) 3·2 A clockwise
Answer: A
5. A long solenoid has length L, average diameter D and n layer of turns. Each layer contains N turns.If current flowing through the solenoid is i the value of magnetic field at the centre_____________
(a) Proportional to D
(b) Inversely proportional to D
(c) Does not depend on D
(d) Proportional to L
Answer: C
6. A long solenoid carrying a current produces a magnetic field B along its axis. If the current is doubled and the number of turns per cm is halved,the new value of the magnetic field is____________
(a) B/2
(b) B
(c) 2B
(d) 4B
Answer: B
7. A long solenoid having 200 turns/cm and carries current i. Magnetic field at its axis is 6·28 × 10-² wb/m2 An another solenoid having 100 turns/cm and carries i3 current, then magnetic field at its axis will be_____________
(1) 1.05 × 10–⁴ Wb/m2
(2) 1.05 × 10–² Wb/m2
(3) 1.05 × 10–⁵ Wb/m2
(4) 1.05 × 10–³ Wb/m2
Answer: B
8. 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 lattice structure of the material of the rod
(d) the induced electric field due to the changing magnetic field
Answer: A
9. A long wire carrying a steady current is bent into a circular loop of one turn. The magnetic field at the centre of the loop is B. It is then bent into a circular coil of n turns. The magnetic field at the centre of this coil of n turns will be__________
(a) 2nB
(b) 2n²B
(c) nB
(d) n²B
Answer: D
10. Biot- savart law is used to determine magnetic field. It is analogous to which law to determine electric field?
(a) Ampere’s law
(b) Lenz law
(c) Faraday’s law
(d) Coulomb’s law
Answer: D
11. Which is ferromagnetic ?
(a) Co
(b) Mg
(c) Ag
(d) Cu
Answer: A
12. 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
13. A long horizontal wire ‘A’ is rigidly fixed and an another wire ‘B’ which is placed directly below and parallel to wire ‘A’. Wire ‘B’ remains suspended in air due to magnetic attraction. If direction of current is reversed in any one wire then due to gravity instantaneous acceleration of free wire ‘B’ (where g is acceleration due to gravity)
(a) g, in downward direction
(b) g, in upward direction
(c) 2g, in dowward direction
(d) 2g, in upward direction
Answer: C
14. Two long parallel current carrying conductors
30 cm apart having current each of 10A in opposite
direction, then value of magnetic field at a point
of 10 cm between them, from any of the wire.
(a) 1 × 10–⁵ T
(b) 6 × 10–⁵ T
(c) 1.5 × 10–⁵ T
(d) 3 × 10–⁵ T
Answer: B
15. A hydrogen ion moving with a velocity of 10⁴m/s enters in magnetic field 10–⁴ T perpendicularly, then its radius of circular path is__________
(a) 10.01 m
(b) 1.01 m
(c) 101 m
(d) 0.101 m
Answer: C
16. Which is a diamegnetic material ?
(a) Ni
(b) Na
(c) Au
(d) Pt
Answer: A
17. Two parallel current carrying wires separated by distance 10 cm attract each other by force of 4 × 10–⁴ N/m. If current in one wire is 10 A, then current in other wire is__________
(a) 20 A
(b) 10 A
(c) 30 A
(d) 5 A
Answer: D
18. In a mass spectrograph, mass number and charge of ion A are 24 and +2e respectively. Mass number and charge of ion B are 22 and +e. If both ions have same speed and the radius of path traced by ion A is 24 cm then radius of path traced by ion B will be___________
(a) 55 cm
(b) 11 cm
(c) 44 cm
(d) 24 cm
Answer: C
19. A charged particle moves through a magnetic field perpendicular to its direction, then________
(a) both momentum and kinetic energy of the particle are not constant
(b) both momentum and kinetic energy of the particle are constant
(c) kinetic energy changes but the momentum is constant
(d) the momentum changes but the kinetic energy is constant
Answer: D
20. A beam of electrons moving along +y direction enters in a region of uniform electric and magnetic fields. If the beam goes undeflected through this region then field (B) and (E) are directed respectively_______
(a) –x axis and +z axis
(b) +z axis and –x axis
(c) +x axis and –z axis
(d) –x axis and –y axis
Answer: B
21. Which of the following is true ?
(a) Diamagnetism is temperature dependent
(b) Paramagnetism is temperature dependent
(c) Paramagnetism is temperature independent
(d) None of these
Answer:B
22. A superconductor exhibits perfect______
(a) Ferrimagnetism
(b) Antierromagnetism
(c) Paramagnetism
(d) Diamagnetism
Answer: D
23. Which of the following statements is incorrect about hysteresis ?
(a) This effect is common to all ferromagnetic substances
(b) The hysteresis loop area is proportional to the thermal energy developed per unit volume of the material
(c) The hysteresis loop area is independent of the thermal energy developed per unit volume of the material
(d) The shape of the hysteresis loop is characteristic of the material
Answer: C
24. A wire of mass 100 gm, length 1m and current 5A is balanced in mid air by a magnetic field B, then find the value of ‘B’ ______
(a) 0.2T
(b) 0.1 T
(c) 0.5 T
(d) 0.6 T
Answer: A
25. A dip circle is taken to geomagnetic equator. The needle is allowed to move in a vertical plane per-pendicular to the magnetic meridian. The needle will stay____________
(a) in horizontal direction only
(b) in vertical direction only
(c) in any direction except vertical and horizontal
(d) in any direction it is released
Answer: D
26. Electromagnets are made of soft iron because soft iron has__________
(a) High retentivity and low coercive force
(b) Low retentivity and high coercive force
(c) High retentivity and high coercive force
(d) Low retentivity and low coercive force
Answer: D
18. A vibration magnetometer placed in magnetic meridian has a small bar magnet. The magnet executes oscillations with a time period of 2 sec in earth’s horizontal magnetic field of 24 microtesla. When a horizontal field of 18 microtesla is produced opposite to the earth’s field by placing a current carrying wire,the new time period of magnet will be__________
(1) 4s
(2) 1s
(3) 2s
(4) 3s
Answer: A
19. A uniform electric field and a uniform magnetic field are acting along the same direction in a certain region. If an electron is projected in the region such that its velocity is pointed along the direction of fields, then the electrons___________
(a) will turn towards right of direction of motion
(b) speed will decrease
(c) speed will increase
(d) will turn towards left of direction of motion
Answer: B
20. There are four light-weight rod samples A,B,C D separately suspended by threads. A bar magnet is slowly brought near each sample and the following observations are noted___________
(i) A is feebly repelled
(ii) B is feebly attracted
(iii) C is strongly attracted
(iv) D remains unaffected
Which one of the following is true ?
(1) B is of a paramagnetic material
(2) C is of a diamagnetic material
(3) D is of a ferromagnetic material
(4) A is of a non-magnetic material
Answer: A
21. Relative perimittivity and permeability of a material
are re and mr
respectively. Which of the following values of these quantities are allowed for a
diamagnetic material :-
(a) e =r 0.5 , m =r 1.5
(b) e =r 1.5 , m =r 0.5
(c) e =r 0.5 , mr =0.5
(d) e =r 1.5 , m =r 1.5
Answer: B
22. A current loop in a magnetic field :-
(a) Can be in equilibrium in two orientations, one
stable while the other is unstable.
(b) Experiences a torque whether the field is
uniform or non uniform in all orientations
(c) Can be in equilibrium in one orientation
(d) Can be in equilibrium in two orientations, both
the equilibrium states are unstable
Answer: A
23. The magnetic moment of a diamagnetic atom is____________
(a) 1
(b) Between zero and one
(c) Equal to zero
(d) Much greater than one
Answer: C
24. The total magnetic flux in a material of area A, which
produces a pole of strength mp when placed in a
magnetic field of strength H, will be :-
(a) µ0
(AH + mp)
(b) µ0
AH
(c) µ0
mp
(d) µ0
[mpAH + A]
Answer: A
25. The magnetic susceptibility of a paramagnetic substance is 3 × 10–⁴. It is placed in magnetising field of 4 × 104 A/m. The intensity of magnetisation will be____________
(a) 3 × 10⁸ A/m
(b) 12 × 10⁸ A/m
(c) 12 A/m
(d) 24 A/m
Answer: C
26. The volume susceptibility of a magnetic material is 30 × 10–⁴. Its relative permeability will be__________
(a) 31 × 10–⁴
(b) 1.003
(c) 1.0003
(d) 29 × 10–⁴
Answer: B
27. The magnetic moment of a magnet of mass
75 gm is 9 × 10–⁷A-m2. If the density of the
material of magnet is 7.5 × 10³ kg/m3 then intensity
of magnetisation will be____________
(a) 0.9 A/m
(b) 0.09 A/m
(c) 9 A/m
(d) 90 A/m
Answer: B
28. The area of hysteresis loop of a material is
equivalent to 250 Joule/m3. When 10 kg material
is magnetised by an alternating field of 50Hz then
energy lost in one hour will be if the density of
material is 7.5 gm/cm³.
(a) 6 × 10⁴ Joule
(b) 6 × 10⁴ Erg
(c) 3 × 10² Joule
(d) 3 × 10² Erg
Answer: A
29. In a mass spectrograph O++, C+, He++ and H+ are projected on a photographic plate with same
velocity in uniform magnetic field then which will
strike the plate farthest_________
(a) O++
(b) C+
(c) He++
(d) H+
Answer: B
30. An ionised gas contains both positive and negative
ions. If it is subjected simultaneously to an electric
field along the + x direction and a magnetic field
along the + z direction then___________
(a) Positive ions deflect towards +y direction and negative ions towards – y direction
(b) All ions deflect towards + y direction
(c) All ions deflect towards – y direction
(d) Positive ions deflect towards – y direction and negative ions towards +y direction
Answer: C