L-3 » Magnetic effect of Current and Magnetism- MCQs (12th) | Physics | Objective Questions- 12th

Multiple Choice

ID- 15653

BSEB, 2019 (C)

1. When magnetic moment of an oscillating magnet increases, its time period will:

(A) imcrease
(B) decrease
(C) remain unchanged
(D) become half

Oct 19, 2022 at 06:14 AM

Multiple Choice

ID- 15654

BSEB, 2019 (C)

2. The angle of magnetic dip at magnetic equator is:

(A) 0°
(B) 90°
(C) 45°
(D) 60°

Oct 19, 2022 at 06:15 AM

Multiple Choice

ID- 15655

BSEB, 2020 (A)

3. The relation between geometrical length $\ce{(L_g)}$ of a magnet and its magnetic length $\ce{(L_m)}$ is:

(A) $\ce{L_m = \frac{5}{6} L_g}$
(B) $\ce{L_m = \frac{6}{5} L_g}$
(C) $\ce{L_m = L_g}$
(D) $\ce{L_m = 2L_g}$

Oct 19, 2022 at 06:21 AM

Multiple Choice

ID- 15656

BSEB, 2020 (A)

4. If δ is the angel of dip at a place, then expression for tan δ is:

(A) $\ce{B_V/B_H}$
(B) $\ce{B_H/B_V}$
(C) $\ce{B_VB_H}$
(D) $\ce{(\frac{B_V}{B_H})^2}$

Oct 19, 2022 at 06:29 AM

Multiple Choice

ID- 15657

BSEB, 2020 (A)

5. On going from north pole to equator, the value of angle of dip:

(A) remains constant
(B) increases
(C) decreases
(D) first decreases and then increases

Oct 19, 2022 at 06:31 AM

Multiple Choice

ID- 15658

BSEB, 2020 (A)

6. Iron is:

(A) paramagnetic
(B) diamagnetic
(C) ferromagnetic
(D) non-magnetic

Oct 19, 2022 at 06:33 AM

Multiple Choice

ID- 15659

BSEB, 2015; 2016

7. The working of dynamo is based on the principal of:

(A) heating effect of current
(B) electromagnetic induction
(C) magnetic induction
(D) electric induction

Oct 19, 2022 at 06:35 AM

Multiple Choice

ID- 15660

BSEB, 2011, 2015

8. Nickel is:

(A) diamagnetic
(B) paramagnetic
(C) ferromagnetic
(D) none of these

Oct 19, 2022 at 06:37 AM

Multiple Choice

ID- 15661

BSEB, 2010

9. A charge moving with uniform velocity produces:

(A) only an electric field
(B) only a magnetic field
(C) electromagnetic field
(D) none of these

Oct 19, 2022 at 06:38 AM

Multiple Choice

ID- 15662

BSEB, 2009

10. The magnetic field at the centre of a circular loop of area A is B. The magnetic moment of the loop will be:

(A) $\ce{\frac{BA^2}{μ_0π}}$
(B) $\ce{\frac{BA^{3/2}}{μ_0}}$
(C) $\ce{\frac{BA^{3/2}}{μ_0π}}$
(D) $\ce{\frac{2BA^{3/2}}{μ_0\sqrt{π}}}$

Oct 19, 2022 at 06:45 AM

Multiple Choice

ID- 15663

BSEB, 2015

11. The direction of propagation of electro-magnetic wave is:

(A) parallel to $\ce{\overset{→}{B}}$
(B) parallel to $\ce{\overset{→}{E}}$
(C) parallel to $\ce{\overset{→}{B} x \overset{→}{E}}$
(D) parallel to $\ce{\overset{→}{E} x \overset{→}{B}}$

Oct 19, 2022 at 04:57 PM

Multiple Choice

ID- 15664

BSEB, 2009

12. If L be the inductance, R resistance and C be the capacitance of a capacitor, then dimensional formulae of $\ce{\frac{L}{R}}$ and RC are:

(A) $\ce{M^0LT^{–1},ML^0T^{–1}}$
(B) $\ce{M^0L^0T,MLT^0}$
(C) $\ce{M^0L^0T, 1}$
(D) $\ce{M^0L^0T, M^0L^0T}$

Oct 19, 2022 at 05:02 PM

Multiple Choice

ID- 15665

BSEB, 2009

13. In tan A and tan B positions of a magnet the magnetic field at a distance are represented by $\ce{B_1}$ and $\ce{B_2}$ respectively, then:

(A) $\ce{B_1 = \frac{μ_0}{4π}·\frac{2Md}{(d^2 – l^2)}, B_2 = \frac{μ_0}{4π}·\frac{M}{(d^2 + l^2)}^{3/2}}$
(B) $\ce{B_1 = B_2; d > > l}$
(C) $\ce{B_1 = 2B_2; d > > l}$
(D) both 'A' and 'B'

Oct 19, 2022 at 05:11 PM

Multiple Choice

ID- 15668

BSEB, 2009

14. The phase difference between electric and magnetic fields in an electromagnetic wave is:

(A) 0
(B) $\ce{\frac{π}{2}}$
(C) π
(D) anything

Oct 19, 2022 at 06:40 PM

Multiple Choice

ID- 15670

BSEB, 2015

15. Dimension of permeability is:

(A) $\ce{MLT^{–2}I^{–2}}$
(B) $\ce{MLT^2I^{–2}}$
(C) $\ce{MLT^2I^2}$
(D) $\ce{MLT^{–2}I}$

Oct 19, 2022 at 06:43 PM

Multiple Choice

ID- 15672

16. A charged particle would continue to move with a constant velocity in a region wherein, which of the following conditions is not correct?

(A) E = 0, B ≠ 0
(B) E ≠ 0, B ≠ 0
(C) E ≠ 0, B = 0
(D) E = 0, B = 0

Oct 19, 2022 at 06:45 PM

Multiple Choice

ID- 15674

17. A strong magnetic field is applied on a stationary electron. Then the electron:

(A) moves in the direction of the field
(B) remains stationary
(C) moves perpendicular to the direction of the field
(D) moves opposite to the direction of the field

Oct 19, 2022 at 06:55 PM

Multiple Choice

ID- 15675

18. A charged particle is moving in a cyclotron, what effect on the radius of path of this charged particle will occur when the frequency of the radio frequency field is doubled?

(A) It will also be doubled
(B) It will be halved
(C) It will be increase by four times
(D) It will remain unchanged

Oct 19, 2022 at 06:58 PM

Multiple Choice

ID- 15677

19. A long straight wire carrying current of 30 A rests on a table. Another wire AB of length 1 m, mass 3gm carries the same current but in the opposite direction, the wire AB is free to slide up and down. The height upon which AB will rise is:

(A) 0.6 cm
(B) 0.7 cm
(C) 0.4 cm
(D) 0.5 cm

Oct 19, 2022 at 07:01 PM

Multiple Choice

ID- 15678

20. A galvanometer of resistance 70 Ω, is converted to an ammeter by a shunt resistance $\ce{r_s}$ = 0.03 Ω. The value of its resistance will become:

(A) 0.025 Ω
(B) 0.022 Ω
(C) 0.035 Ω
(D) 0.030 Ω

Oct 19, 2022 at 07:06 PM

Multiple Choice

ID- 15679

21. A circular coil of radius 10 cm having 100 turns carries a current of 3.2 A. The magnetic field at the center of the coil is:

(A) 2.01 x $\ce{10^{–3}}$ T
(B) 5.64x $\ce{10^{–3}}$ T
(C) 2.64 x $\ce{10^{–4}}$ T
(D) 5.64x $\ce{10^{–4}}$ T

Oct 19, 2022 at 07:10 PM

Multiple Choice

ID- 15680

22. The energy of an electron having a speed of 2.98 x $\ce{10^7 ms^{–1}}$ is (m = 9.1 x $\ce{10^{–31}}$ kg):

(A) 2.2 KeV
(B) 2.5 KeV
(C) 2.8 KeV
(D) 3.0 KeV

Oct 19, 2022 at 07:13 PM

Multiple Choice

ID- 15682

23. The cyclotron frequency v is given by:

(A) $\frac{qB}{2πm}$
(B) $\frac{mB}{2πm}$
(C) $\frac{2πm}{qB}$
(D) $\frac{2πB}{qm}$

Oct 19, 2022 at 07:16 PM

Multiple Choice

ID- 15686

24. The magnitude of the magnetic field at the centre of the tightly wound 150 turn coil of radius 12 cm carrying a current of 2A is:

(A) 18 G
(B) 19.7 G
(C) 15.7 G
(D) 17.7 G

Oct 19, 2022 at 07:26 PM

Multiple Choice

ID- 15687

25. A circular loop of radius 3 cm is having a current of 12.5 A. The magnitude of magnetic filed at a distance of 4 cm on its axis is:

(A) 5.65 x $\ce{10^{–5}}$ T
(B) 5.27 x $\ce{10^{–5}}$ T
(C) 6.54x $\ce{10^{–5}}$ T
(D) 9.20x $\ce{10^{–5}}$ T

Oct 19, 2022 at 07:29 PM

Multiple Choice

ID- 15688

26. Ampere's circular law is given by:

(A) $\oint \overset{→}{H}.\overset{→}{dl} = μ_0I_{enc}$
(B) $\oint \overset{→}{B}.\overset{→}{dl} = μ_0I_{enc}$
(C) $\oint \overset{→}{B}.\overset{→}{dl} = μ_0J$
(D) $\oint \overset{→}{H}.\overset{→}{dl} = μ_0J$

Oct 19, 2022 at 07:34 PM

Multiple Choice

ID- 15689

27. Which on the following statement is correct?

(A) The magnetic field in the open space inside the toroid is constant
(B) The magnetic field in the open space exterior to the toroid is constant
(C) The magnetic field inside the core of toroid is constant
(D) The magnetic field inside the core of toroid is zero

Oct 19, 2022 at 07:37 PM

Multiple Choice

ID- 15690

28. A current carrying loop is placed in an uniform magnetic field: The torque acting on it does not depend upon:

(A) shape of loop
(B) area of loop
(C) value of current
(D) magnetic field

Oct 19, 2022 at 07:40 PM

Multiple Choice

ID- 15692

BSEB, 2021 (A)

29. Expression of force on a charge q moving with velocity $\overset{→}{V}$ in a magnetic field $\overset{→}{B}$ is:

(A) $\ce{\overset{→}{F}m = q (\overset{→}{V} x \overset{→}{B})}$
(B) $\ce{\overset{→}{F}m = q (\overset{→}{B} x \overset{→}{V})}$
(C) $\ce{\overset{→}{F}m = \frac{\overset{→}{B} x \overset{→}{V}}{q}}$
(D) $\ce{\overset{→}{F}m = \frac{\overset{→}{V} x \overset{→}{B}}{q}}$

Oct 19, 2022 at 07:53 PM

Multiple Choice

ID- 15693

BSEB, 2021 (A)

30. Agnetic field of 5 tesla is equal to:

(A) $\ce{5 x \frac{weber}{(metre)^2}}$
(B) $\ce{5 x 10^5 \frac{weber}{(metre)^2}}$
(C) $\ce{5 x 10^2 \frac{weber}{(metre)^2}}$
(D) $\ce{5 x 10^2 weber x (metre)^2}$

Oct 19, 2022 at 07:57 PM

Multiple Choice

ID- 15695

31. The value of magnetic susceptibility of vacuum is:

(A) equal to 0.5
(B) infinite
(C) equal to one
(D) zero

Oct 19, 2022 at 07:58 PM

Multiple Choice

ID- 15697

32. The gyromagnetic ratio of an electron in sodium atom is:

(A) depending upon the atomic number of the atom
(B) depending upon the shell number of the atom
(C) independent of that orbit it is in
(D) having positive value

Oct 19, 2022 at 08:00 PM

Multiple Choice

ID- 15698

33. If the current sensitivity of a galvanometer is doubled, then its voltage sensitivity will be:

(A) doubled
(B) halved
(C) unchanged
(D) four times

Oct 19, 2022 at 08:02 PM

Multiple Choice

ID- 15700

34. 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

Oct 19, 2022 at 08:07 PM

Multiple Choice

ID- 15703

35. Two $\propto$-particles have the ratio of their velocities as 3 : 2 on entering the field. If they moving 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

Oct 19, 2022 at 08:18 PM

Multiple Choice

ID- 15704

BSEB, 2018 (C)

36. An electron in travelling horizontally toward East. A magnetic field in vertically downward direction exerts a force on the electron along:

(A) South
(B) East
(C) West
(D) North

Oct 19, 2022 at 08:20 PM

Multiple Choice

ID- 15705

BSEB 2018 (C)

37. The area of cross sections of three magnets of same lengths are A, 2A and 6A respectively. The ratio of their magnetic moments will be:

(A) 6 : 2 : 1
(B) 1 : 2 : 6
(C) 2 : 6 : 1
(D) 1 : 1 : 1

Oct 19, 2022 at 08:24 PM

Multiple Choice

ID- 15707

BSEB, 2018 (C), 2020 (A)

38. Lorentz force is given by:

(A) $\ce{q (\overset{→}{E} + \overset{→}{B})}$
(B) $\ce{q (\overset{→}{E} + \overset{→}{V}·\overset{→}{B})}$
(C) $\ce{q (\overset{→}{E} + \overset{→}{B} X \overset{→}{V})}$
(D) $\ce{q (\overset{→}{E}+\overset{→}{V} X \overset{→}{B})}$

Oct 19, 2022 at 08:28 PM

Multiple Choice

ID- 15708

BSEB, 2018 (C)

39. When a charged particle moves in a region containing a magnetic field, then:

(A) The magnetic of its velocity keeps on changing.
(B) The velocity of particle remains constant.
(C) The direction of its Linear Momentum keeps on changing.
(D) The Kinetic energy of particle keeps on charging.

Oct 19, 2022 at 08:32 PM

Multiple Choice

ID- 15710

BSEB, 2019 (C)

40. What is the angel of dip at the magnetic poles?

(A) 30°
(B) 0°
(C) 45°
(D) None of these

Oct 19, 2022 at 08:34 PM

Multiple Choice

ID- 15711

41. Circular loop of radius 0.0157 m carries a current 2 A. The magnetic field at the centre of the loop is:

(A) 1.57 x $\ce{10^{–5} Wb/m^2}$
(B) 8.0x $\ce{10^{–5} Wb/m^2}$
(C) 2.0 x $\ce{10^{–5} Wb/m^2}$
(D) 3.14x $\ce{10^{–1} Wb/m^2}$

Oct 19, 2022 at 08:37 PM

Multiple Choice

ID- 15712

BSEB, 2019 (A)

42. The Torque. $(\overset{→}{\tau})$experienced by a curent-loop of magnetic moment $(\overset{→}{M})$ placed in magnetic field $\overset{→}{B}$ is

(A) $\overset{→}{\tau} = \overset{→}{M} x \overset{→}{B}$
(B) $\overset{→}{\tau} = \overset{→}{B} x \overset{→}{M}$
(C) $\overset{→}{\tau} = \frac{\overset{→}{M}}{\overset{→}{B}}$
(D) $\overset{→}{\tau} = \overset{→}{M}·\overset{→}{B}$

Oct 19, 2022 at 08:46 PM

Multiple Choice

ID- 15713

BSEB, 2018 (C)

43. Which of the following substances have a tendency to move from stronger to the weaker part of an external magnetic field?

(A) Paramagnetic
(B) Diamagnetic
(C) Ferromagnetic
(D) None of the above

Oct 19, 2022 at 08:48 PM

Multiple Choice

ID- 15715

44. Which of the following is not a unit of magnetic induction?

(A) gauss
(B) tesla
(C) oersted
(D) $\ce{weber/metre^2}$

Oct 19, 2022 at 08:52 PM

Multiple Choice

ID- 15720

BSEB, 2019 (A)

45. In earth's magnetic field $\ce{B_H}$, If the frequency of oscillation of a magnetic needle is n, then

(A) $\ce{n \propto B_H}$
(B) $\ce{n^2 \propto B_H}$
(C) $\ce{n \propto B^2_H}$
(D) $\ce{n^2 \propto \frac{1}{B_H}}$

Oct 20, 2022 at 04:57 AM

Multiple Choice

ID- 15721

46. According to Ampere's Circuital law,

(A) $\oint\overset{→}{B} x \overset{→}{dl} = 0$
(B) $\oint\overset{→}{B}.\overset{→}{dl} = μ_0I$
(C) $\oint\overset{→}{B} x \overset{→}{dl} = 1$
(D) $\oint\overset{→}{B} x \overset{→}{dl} = \frac{μ_0I}{4π}$

Oct 20, 2022 at 05:01 AM

Multiple Choice

ID- 15722

47. How much force will be experienced by a moving charge in a magnetic field? The symbols have their usual meanings:

(A) $\overset{→}{F} = q (\overset{→}{v} . \overset{→}{B})$
(B) $\overset{→}{F} = \frac{q}{(\overset{→}{v} . \overset{→}{B})}$
(C) $\overset{→}{F} = \frac{q}{2}(\overset{→}{v} x \overset{→}{B})$
(D) $\overset{→}{F} = q (\overset{→}{v} x \overset{→}{B})$

Oct 20, 2022 at 05:25 AM

Multiple Choice

ID- 15723

48. A charge +q is sent through a magnetic field. The force acting on it is maximum when the angle between the direction of motion of the charged particle and the magnetic field:

(A) 0°
(B) 45°
(C) 90°
(D) 180°

Oct 20, 2022 at 05:27 AM

Multiple Choice

ID- 15724

49. A wire of length 2 metre carries a current 1 ampere, is bent to form a circle. The magnetic moment of the coil is:

(A) 2π
(B) π / 2
(C) π / 4
(D) 1 / π

Oct 20, 2022 at 05:29 AM

Multiple Choice

ID- 15725

BSEB, 2019 (A), 2021 (A)

50. The value of angle of dip at the earth's magnetic pole is:

(A) 0°
(B) 45°
(C) 90°
(D) 180°

Oct 20, 2022 at 05:30 AM

Multiple Choice

ID- 15726

51. When charged particle enters a uniform magnetic field, its K.E.:

(A) remains constant
(B) increases
(C) decreases
(D) becomes zero

Oct 20, 2022 at 05:32 AM

Multiple Choice

ID- 15727

52. Isoclinic lines are the lines joining places with:

(A) equal dip
(B) equal declination
(C) equal dip & declination
(D) None of these

Oct 20, 2022 at 05:33 AM

Multiple Choice

ID- 15728

BSEB, 2021 (A)

53. If B is earth's magnetic field in magnetic meridian, δ is angle of dip, $\ce{B_H}$ is horizontal component of $\overset{→}{B}$ and $\ce{B_V}$ is vertical component of $\overset{→}{B}$, then which of the following relations is correct?

(A) $\ce{B_H = Bcosδ}$
(B) $\ce{B_V = Bcosδ}$
(C) $\ce{B_H = Bsinδ}$
(D) $\ce{B_V = B_Hsinδ}$

Oct 20, 2022 at 05:39 AM

Multiple Choice

ID- 15729

54. The most suitable metal for making permanent magnets is:

(A) iron
(B) steel
(C) copper
(D) aluminum

Oct 20, 2022 at 05:40 AM

Multiple Choice

ID- 15730

BSEB, 2016

55. The SI unit of magnetic dipole moment is:

(A) Ampere
(B) Ampere $metre^2$
(C) Tesla
(D) None of these

Oct 20, 2022 at 05:41 AM

Multiple Choice

ID- 15731

56. Earth's magnetism was discovered by:

(A) Gauss
(B) Oested
(C) Ampere
(D) Gilbert

Oct 20, 2022 at 05:42 AM

Multiple Choice

ID- 15732

57. According to Gauss's theorem in magnetism, surface integral of magnetic field intensity over a surface (closed or open) is always:

(A) –1
(B) 1
(C) 0
(D) infinity

Oct 20, 2022 at 05:44 AM

Multiple Choice

ID- 15733

BSEB, 2019 (C)

58. Tesla is a unit of:

(A) electric flux
(B) magnetic flux
(C) magnetic field
(D) electric field

Oct 20, 2022 at 05:45 AM

Multiple Choice

ID- 15734

59. 10 eV electron is circulating in a plane at right angle to a uniform filed of magnetic induction $\ce{10^{–4} Wb/m^2}$ (1G). The orbital radius of electron is:

(A) 12 cm
(B) 16 cm
(C) 11 cm
(D) 18 cm

Oct 20, 2022 at 05:48 AM

Multiple Choice

ID- 15735

60. A cyclotron can be used to produce high energy:

(A) neutrons
(B) deutrons
(C) β particles
(D) α particles

Oct 20, 2022 at 05:50 AM

Multiple Choice

ID- 15736

61. The radius of the trajectory of a charged particel in a uniform magnetic filed is proportional to the:

(A) charge on the particle
(B) energy of the particle
(C) momentum of the particle
(D) all the above

Oct 20, 2022 at 05:52 AM

Multiple Choice

ID- 15737

62. If in a hollow pipe of copper, current is flowing, then the produced magnetic field will be:

(A) only inside the pipe
(B) only outside the pipe
(C) neither inside nor outside
(D) inside and outside both

Oct 20, 2022 at 05:56 AM

Multiple Choice

ID- 15738

63. A barmagnet of magnetic moment p is divided into two equal parts by cutting it perpendicular to its length. Then the pieces will have a magnetic moment of

(A) 2p
(B) p
(C) $\frac{p}{2}$
(D) zero

Oct 20, 2022 at 05:58 AM

Multiple Choice

ID- 15739

64. The magnetic moment per unit volume is called:

(A) magnetising field
(B) magnetic induction
(C) magnetisation
(D) magnetic permeability

Oct 20, 2022 at 06:00 AM

Multiple Choice

ID- 15740

65. The dimensions of $\sqrt{μ_0\varepsilon_0}$ are same as that of:

(A) velocity
(B) acceleration
(C) $\frac{1}{velocity}$
(D) $\frac{1}{acceleration}$

Oct 20, 2022 at 06:03 AM

Multiple Choice

ID- 15741

66. A small piece of substance gets repelled by a strong permanent magnet. The substance must necessarily be:

(A) diamagnetic
(B) paramagnetic
(C) ferromagnetic
(D) ferrite

Oct 20, 2022 at 06:05 AM

Multiple Choice

ID- 15742

67. What is non-magnetic substance?

(A) It has a low permeability.
(B) It has a low susceptibility.
(C) It gets demagnetised in an external magnetic filed.
(D) It does not get magnetised in an external magnetic field.

Oct 20, 2022 at 06:08 AM

Multiple Choice

ID- 15743

68. Under identical conditions, the ratio of the magnetic to the electrostatic force is:

(A) $\ce{10^{27}}$
(B) $\ce{10^{17}}$
(C) $\ce{10^{–17}}$
(D) $\ce{10^{–27}}$

Oct 20, 2022 at 06:10 AM

Multiple Choice

ID- 15744

69. The moving coil galvanometer is based upon the principal of:

(A) interaction of charge and electric field
(B) interaction of current and magnetic field
(C) Faraday's law
(D) Maxwell's assumption

Oct 20, 2022 at 06:12 AM

Multiple Choice

ID- 15745

70. The SI unit for $μ_0$ is:

(A) $\ce{T}$
(B) $\ce{TmA^{–1}}$
(C) $\ce{TmA^{–2}}$
(D) $\ce{Tm^2A^{–1}}$

Oct 20, 2022 at 06:17 AM

Multiple Choice

ID- 15746

BSEB, 2021 (A)

71. Which of the following relation is correct fir permeability?

(A) $μ = \frac{H}{B}$
(B) $μ = \frac{B}{H}$
(C) $μ = B · H$
(D) $μ = (B + H) $

Oct 20, 2022 at 06:20 AM

Multiple Choice

ID- 15747

72. The S.I. unit of magnetic permeability is:

(A) $\ce{Wb m^{–2} A^{–1}}$
(B) $\ce{Wb m^{–1} A^{–1}}$
(C) $\ce{Wb m^{–2} A}$
(D) $\ce{Wb m A}$

Oct 20, 2022 at 06:22 AM

Multiple Choice

ID- 15748

73. Two protons enter into uniform magnetic field with velocities ratio 2 : 1 and follow the circular paths. The ratio of their frequencies will be:

(A) 2 : 1
(B) 1 : 2
(C) 1 : 1
(D) 4 : 1

Oct 20, 2022 at 06:24 AM

Multiple Choice

ID- 15749

74. The magnetic dipole moment of a current loop does not depends on the:

(A) number of turns
(B) area of the loop
(C) current in the loop
(D) magnetic field in which it is kept

Oct 20, 2022 at 06:26 AM

Multiple Choice

ID- 15750

75. The pitch of the helical path followed by charged particle in magnetic field does not depend upon the:

(A) B
(B) V
(C) v
(D) q

Oct 20, 2022 at 06:27 AM

Multiple Choice

ID- 15751

76. The time period of a freely suspended magnet does not depend upon the:

(A) Length of the magnet
(B) pole strength of the magnet
(C) length of the suspension
(D) horizontal component of earth's magnetic field

Oct 20, 2022 at 08:55 AM

Multiple Choice

ID- 15752

77. In thomson spectro graph $\ce{\overset{→}{E} \perp \overset{→}{B}}$, then velocity of electron beam will be:

(A) $\ce{|\overset{→}{E}|/|\overset{→}{B}|}$
(B) $\overset{→}{E} x \overset{→}{B}$
(C) $\ce{|\overset{→}{B}|/|\overset{→}{E}|}$
(D) $\ce{E^2/B^2}$

Oct 20, 2022 at 06:34 PM

Multiple Choice

ID- 15753

78. To send 10% of the main current through a moving coil galvanometer of resistance 99 Ω the shunt required is:

(A) 9.9 Ω
(B) 10 Ω
(C) 11 Ω
(D) 9 Ω

Oct 20, 2022 at 06:40 PM

Multiple Choice

ID- 15754

79. S.I.unit of flux is:

(A) Ohn
(B) Weber
(C) Tesla
(D) None

Oct 20, 2022 at 06:41 PM

Multiple Choice

ID- 15755

80. Which of the following has a low value in ferrites?

(A) Conductivity
(B) Permeability
(C) Magnetic susceptibility
(D) All the above

Oct 20, 2022 at 06:42 PM

Multiple Choice

ID- 15756

81. The dimensional representation of magnetic flux density is:

(A) $\ce{[MLT^{–2}]}$
(B) $\ce{[MLT^{–2}A^{–1}]}$
(C) $\ce{[MLT^{–2}A^{–2}]}$
(D) $\ce{[MLT^{–2}A^{–1}]}$

Oct 20, 2022 at 06:44 PM

Multiple Choice

ID- 15757

82. Tangent law is applicable only when:

(A) two uniform and matually 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

Oct 20, 2022 at 06:47 PM

Multiple Choice

ID- 15758

83. Ferrites may be:

(A) ant. ferromagnetic
(B) ferromagnetic
(C) ferrimagnetic
(D) None of the above

Oct 20, 2022 at 06:48 PM

Multiple Choice

ID- 15759

84. The magnetic lines of force inside a bar magnet:

(A) do not exist
(B) depends on area of cross-section of bar magnet
(C) are from N-pole to s-pole of the magnet
(D) are from S-pole to N-pole of the magnetic

Oct 20, 2022 at 06:50 PM

Multiple Choice

ID- 15760

BSEB, 2018 (A)

85. 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

Oct 20, 2022 at 06:51 PM

Multiple Choice

ID- 15761

86. The dimensional representation of $\sqrt{I / MB}$ is similar to that of:

(A) frequency
(B) time
(C) distance
(D) speed

Oct 20, 2022 at 06:52 PM

Multiple Choice

ID- 15762

87. On quadrupling the moment of inertia of a magnet, it's frequency of oscillation will become:

(A) half
(B) double
(C) four times
(D) one-fourth

Oct 20, 2022 at 07:58 PM

Multiple Choice

ID- 15763

88. In a moving coil galvanometer, we use a radical magnetic field so that the galvanometer scale is:

(A) exponential
(B) linear
(C) algerbraic
(D) logarithmic

Oct 20, 2022 at 07:10 PM

Multiple Choice

ID- 15764

89. The force between two parallel wire 2 x $\ce{10^{–7} Nm^{–1}}$, placed 1 m apart to each other in vacuum. The electric current flowing through the wires is:

(A) 1 A
(B) zero
(C) 5 x $\ce{10^6}$ A
(D) 2 x $\ce{10^{–7}}$ A

Oct 20, 2022 at 07:13 PM

Multiple Choice

ID- 15765

90. Which of the following has higher magnetic susceptibility:

(A) diamagnetic
(B) paramagnetic
(C) ferromagnetic
(D) None of these

Oct 20, 2022 at 07:15 PM

Multiple Choice

ID- 15766

91. The magnetic field of earth is due to:

(A) induction effect of the sum
(B) the presence of a large magnet at the centre of the earth
(C) interaction of cosmic rays with the current of earth
(D) motion and distribution of some material in an outside the earth

Oct 20, 2022 at 07:19 PM

Multiple Choice

ID- 15767

BSEB, 2017 (C)

92. A straight conducting rod held horizontal along east-west is released to fall, Potential difference a across it will:

(A) be zero
(B) increase
(C) decrease
(D) change direction

Oct 20, 2022 at 07:21 PM

Multiple Choice

ID- 15768

93. The Mariner's compass is provided with Gim bals arrangement so as to:

(A) keep the needle always horizontal
(B) give a direct reading of declination
(C) give the direct value of dip
(D) all of the above

Oct 20, 2022 at 07:23 PM

Multiple Choice

ID- 15769

94. In a cyclotron the angular frequency of the charged particle in independent of the:

(A) mass
(B) speed
(C) charge
(D) magnetic field

Oct 20, 2022 at 07:24 PM

Multiple Choice

ID- 15770

95. A wire of length 2 m carrying a current of I ampere is bent to form a circle. The magnetic moment of the coil is:

(A) $\frac{I}{π}$
(B) $\frac{2}{π}$
(C) 2π
(D) 4π

Oct 20, 2022 at 07:26 PM

Multiple Choice

ID- 15771

96. A galvanometer having a resistance of 8 Ω is shunted by a wire of 2 Ω. If the total current is 1 A, the part of it passing through the shunt will be:

(A) 0.20 A
(B) 0.25 A
(C) 0.50 A
(D) 0.80 A

Oct 20, 2022 at 07:29 PM

Multiple Choice

ID- 15772

97. Cathode rays enter into a uniform magnetic field perpendicular to the direction of the field. In the magnetic field their path will be:

(A) parabolic
(B) straight line
(C) circle
(D) ellipse

Oct 20, 2022 at 07:31 PM

Multiple Choice

ID- 15773

98. At isogonic line:

(A) angle of dip are equal
(B) angle of declination are equal
(C) horizontal components of earth magnetic are equal
(D) vertical components of earth magnetic field are equal

Oct 20, 2022 at 07:32 PM

Multiple Choice

ID- 15774

99. Longitudinally, magnetic lines of force:

(A) contract
(B) expand
(C) interest
(D) remains parallel

Oct 20, 2022 at 07:34 PM

Multiple Choice

ID- 15775

100. Curies law states that:

(A) magnetic susceptibility is inversely proportional to the absolute temperature
(B) magnetic susceptibility is inverse proportional to square root of the absolute temperature
(C) magnetic susceptibility is directly proportional to the absolute temperature
(D) magnetic susceptibility is directly proportional to square root of the absolute temperature

Oct 20, 2022 at 07:37 PM

Multiple Choice

ID- 15776

101. Susceptibility is +ve and large for .......... sunstsnces.

(A) ferromagnetic
(B) paramagnetic
(C) diamagnetic
(D) non-magnetic

Oct 20, 2022 at 07:39 PM

Multiple Choice

ID- 15777

2016 (C)

102. Which of the following substance have negative and very large value of permeability?

(A) ferromagnetic
(B) paramagnetic
(C) diamagnetic
(D) None of these

Oct 20, 2022 at 07:41 PM

Multiple Choice

ID- 15778

103. A voltmeter has resistance of 2000 Ω and it can measure upto 2V. If we want to increase its range to 10 V, then required resistance in series will be:

(A) 2000 V
(B) 4000 V
(C) 6000 V
(D) 8000 V

Oct 20, 2022 at 07:46 PM

Multiple Choice

ID- 15779

104. If only 2% of the main current is to be passed through a galvanometer of resistance G, then the resistance of the shunt will be:

(A) $\frac{G}{50}$
(B) 59 G
(C) $\frac{G}{49}$
(D) 49 G

Oct 20, 2022 at 07:47 PM

Multiple Choice

ID- 15780

105. A dip needle in a plane perpendicular magnetic meridian will remain:

(A) horizontal
(B) vertical
(C) at 45° with horizontal
(D) at 90° with vertical

Oct 20, 2022 at 07:50 PM

Multiple Choice

ID- 15781

106. An isolated magnetic pole is:

(A) made of ferromagnetic substance
(B) made of paramagnetic substance
(C) a current loop
(D) a fictitious quantity

Oct 20, 2022 at 07:51 PM

Multiple Choice

ID- 15782

107. The time period (T) of a freely suspended magnet does not depend upon:

(A) length of the magnet
(B) the pole strength of magnet
(C) the horizontal compound of magnetic field
(D) length of suspension

Oct 20, 2022 at 07:56 PM

Multiple Choice

ID- 15783

BSEB, 2016

108. When the intensity of magnetic field is increased four times, the time-period of suspended magnetic needle becomes:

(A) double
(B) half
(C) four times
(D) one-fourth less

Oct 20, 2022 at 07:58 PM

Multiple Choice

ID- 15784

BSEB, 2016 (C)

109. Moving charge produces:

(A) Only electric field
(B) Only magnetic field
(C) Both magnetic and magnetic field
(D) None of these

Oct 20, 2022 at 08:00 PM

Multiple Choice

ID- 15785

BSEB, 2016 (C)

110. The ratio of peak value and r.m.s. value of AC is:

(A) 2
(B) $\sqrt{2}$
(C) $\frac{1}{\sqrt{2}}$
(D) $\frac{1}{2}$

Oct 20, 2022 at 08:02 PM

Multiple Choice

ID- 15786

BSEB, 2017 (A), 2021 (A)

111. S.I. Unit of pole strength is

(A) N
(B) N/A-m
(C) A-m
(D) T

Oct 20, 2022 at 08:04 PM

Multiple Choice

ID- 15787

BSEB, 2017 (A)

112. Absorved electrical energy is

(A) Proportional to the portential difference
(B) Inversely proportional to the potential difference
(C) Proportional to the square of the potential difference
(D) None of these

Oct 20, 2022 at 08:06 PM

Multiple Choice

ID- 15788

BSEB, 2017 (C)

113. Energy density of a magnetic field $\overset{→}{B}$ is:

(A) $\frac{B^2}{μ_0}$
(B) $\frac{B^2}{2μ_0}$
(C) $\frac{B^2}{3μ_0}$
(D) $\frac{B^2}{4μ_0}$

Oct 20, 2022 at 08:08 PM

Multiple Choice

ID- 15789

BSEB, 2017 (C)

114. Unit of flux of magnetic field is:

(A) tesla
(B) henry
(C) weber
(D) joule-second

Oct 20, 2022 at 08:09 PM

Multiple Choice

ID- 15790

BSEB, 2016,2017 (A)

115. SI unit of magnetic pole strength is:

(A) Ampere-metre
(B) Ampere-$metre^2$
(C) $Ampere^2$-metre
(D) Tesla-metre

Oct 20, 2022 at 08:11 PM

Multiple Choice

ID- 15791

BSEB, 2018 (A)

116. The Drift velocity $\ce{(V_d)}$ and applied electric field (E) of a conductor are related as:

(A) $\ce{V_d \propto\sqrt{E}}$
(B) $\ce{V_d \propto E}$
(C) $\ce{V_d \propto E^2}$
(D) $\ce{V_d = constant}$

Oct 20, 2022 at 08:15 PM

Multiple Choice

ID- 15792

BSEB, 2018 (A)

117. A bar magnet of magnetic moment M is cut into two parts of equal length. The magnetic moment of either part is:

(A) M
(B) M/2
(C) 2M
(D) Zero

Oct 20, 2022 at 08:16 PM

Multiple Choice

ID- 15793

BSEB, 2018 (A)

118. A wire of magnetic dipole moment M and L is bent into shape of a semicircle of radius r. What will be its new dipole moment?

(A) M
(B) $\frac{M}{2π}$
(C) $\frac{M}{π}$
(D) $\frac{2M}{π}$

Oct 20, 2022 at 08:18 PM

Multiple Choice

ID- 15794

BSEB, 2017 (C)

119. A circular coil is held in vertical plane. A bar magnet is taken towards it with North Pole towards coil. Direction of current as seen from the side of magnet is:

(A) anticlockwise
(B) clockwise
(C) first anticlockwise and then clockwise
(D) first clockwise and then anticlockwise

Oct 20, 2022 at 08:21 PM

Magnetic effect of Current and Magnetism

Board » Bihar Board » Class 12th » English Medium » Science » Physics » L-3: Magnetic effect of Current and Magnetism

Objective Questions (MCQs)

1. When magnetic moment of an oscillating magnet increases, its time period will:

2. The angle of magnetic dip at magnetic equator is:

3. The relation between geometrical length $\ce{(L_g)}$ of a magnet and its magnetic length $\ce{(L_m)}$ is:

4. If δ is the angel of dip at a place, then expression for tan δ is:

5. On going from north pole to equator, the value of angle of dip:

6. Iron is:

7. The working of dynamo is based on the principal of:

8. Nickel is:

9. A charge moving with uniform velocity produces:

10. The magnetic field at the centre of a circular loop of area A is B. The magnetic moment of the loop will be:

11. The direction of propagation of electro-magnetic wave is:

12. If L be the inductance, R resistance and C be the capacitance of a capacitor, then dimensional formulae of $\ce{\frac{L}{R}}$ and RC are:

13. In tan A and tan B positions of a magnet the magnetic field at a distance are represented by $\ce{B_1}$ and $\ce{B_2}$ respectively, then:

14. The phase difference between electric and magnetic fields in an electromagnetic wave is:

15. Dimension of permeability is:

16. A charged particle would continue to move with a constant velocity in a region wherein, which of the following conditions is not correct?

17. A strong magnetic field is applied on a stationary electron. Then the electron:

18. A charged particle is moving in a cyclotron, what effect on the radius of path of this charged particle will occur when the frequency of the radio frequency field is doubled?

19. A long straight wire carrying current of 30 A rests on a table. Another wire AB of length 1 m, mass 3gm carries the same current but in the opposite direction, the wire AB is free to slide up and down. The height upon which AB will rise is:

20. A galvanometer of resistance 70 Ω, is converted to an ammeter by a shunt resistance $\ce{r_s}$ = 0.03 Ω. The value of its resistance will become:

21. A circular coil of radius 10 cm having 100 turns carries a current of 3.2 A. The magnetic field at the center of the coil is:

22. The energy of an electron having a speed of 2.98 x $\ce{10^7 ms^{–1}}$ is (m = 9.1 x $\ce{10^{–31}}$ kg):

23. The cyclotron frequency v is given by:

24. The magnitude of the magnetic field at the centre of the tightly wound 150 turn coil of radius 12 cm carrying a current of 2A is:

25. A circular loop of radius 3 cm is having a current of 12.5 A. The magnitude of magnetic filed at a distance of 4 cm on its axis is:

26. Ampere's circular law is given by:

27. Which on the following statement is correct?

28. A current carrying loop is placed in an uniform magnetic field: The torque acting on it does not depend upon:

29. Expression of force on a charge q moving with velocity $\overset{→}{V}$ in a magnetic field $\overset{→}{B}$ is:

30. Agnetic field of 5 tesla is equal to:

31. The value of magnetic susceptibility of vacuum is:

32. The gyromagnetic ratio of an electron in sodium atom is:

33. If the current sensitivity of a galvanometer is doubled, then its voltage sensitivity will be:

34. The conversion of a moving coil galvanometer into a voltmeter is done by:

35. Two $\propto$-particles have the ratio of their velocities as 3 : 2 on entering the field. If they moving different circular paths, then the ratio of the radii of their paths is:

36. An electron in travelling horizontally toward East. A magnetic field in vertically downward direction exerts a force on the electron along:

37. The area of cross sections of three magnets of same lengths are A, 2A and 6A respectively. The ratio of their magnetic moments will be:

38. Lorentz force is given by:

39. When a charged particle moves in a region containing a magnetic field, then:

40. What is the angel of dip at the magnetic poles?

41. Circular loop of radius 0.0157 m carries a current 2 A. The magnetic field at the centre of the loop is:

42. The Torque. $(\overset{→}{\tau})$experienced by a curent-loop of magnetic moment $(\overset{→}{M})$ placed in magnetic field $\overset{→}{B}$ is

43. Which of the following substances have a tendency to move from stronger to the weaker part of an external magnetic field?

44. Which of the following is not a unit of magnetic induction?

45. In earth's magnetic field $\ce{B_H}$, If the frequency of oscillation of a magnetic needle is n, then

46. According to Ampere's Circuital law,

47. How much force will be experienced by a moving charge in a magnetic field? The symbols have their usual meanings:

48. A charge +q is sent through a magnetic field. The force acting on it is maximum when the angle between the direction of motion of the charged particle and the magnetic field:

49. A wire of length 2 metre carries a current 1 ampere, is bent to form a circle. The magnetic moment of the coil is:

50. The value of angle of dip at the earth's magnetic pole is:

51. When charged particle enters a uniform magnetic field, its K.E.:

52. Isoclinic lines are the lines joining places with:

53. If B is earth's magnetic field in magnetic meridian, δ is angle of dip, $\ce{B_H}$ is horizontal component of $\overset{→}{B}$ and $\ce{B_V}$ is vertical component of $\overset{→}{B}$, then which of the following relations is correct?

54. The most suitable metal for making permanent magnets is:

55. The SI unit of magnetic dipole moment is:

56. Earth's magnetism was discovered by:

57. According to Gauss's theorem in magnetism, surface integral of magnetic field intensity over a surface (closed or open) is always:

58. Tesla is a unit of:

59. 10 eV electron is circulating in a plane at right angle to a uniform filed of magnetic induction $\ce{10^{–4} Wb/m^2}$ (1G). The orbital radius of electron is:

60. A cyclotron can be used to produce high energy:

61. The radius of the trajectory of a charged particel in a uniform magnetic filed is proportional to the:

62. If in a hollow pipe of copper, current is flowing, then the produced magnetic field will be:

63. A barmagnet of magnetic moment p is divided into two equal parts by cutting it perpendicular to its length. Then the pieces will have a magnetic moment of

64. The magnetic moment per unit volume is called:

65. The dimensions of $\sqrt{μ_0\varepsilon_0}$ are same as that of:

66. A small piece of substance gets repelled by a strong permanent magnet. The substance must necessarily be:

67. What is non-magnetic substance?

68. Under identical conditions, the ratio of the magnetic to the electrostatic force is:

69. The moving coil galvanometer is based upon the principal of:

70. The SI unit for $μ_0$ is:

71. Which of the following relation is correct fir permeability?

72. The S.I. unit of magnetic permeability is:

73. Two protons enter into uniform magnetic field with velocities ratio 2 : 1 and follow the circular paths. The ratio of their frequencies will be:

74. The magnetic dipole moment of a current loop does not depends on the:

75. The pitch of the helical path followed by charged particle in magnetic field does not depend upon the:

76. The time period of a freely suspended magnet does not depend upon the:

77. In thomson spectro graph $\ce{\overset{→}{E} \perp \overset{→}{B}}$, then velocity of electron beam will be: