IIT JEE MCQ Quiz Hub

1. A charged particle moving in a uniform magnetic field and losses 4% of its KE. The radius of curvature of its path changes by:
2%
4%
10%
none of these

2. wo charged particles each of mass m and charge q are projected in a uniform magnetic field B with the same speed as such planes of motion of particles are perpendicular to magnetic field B then:
they move on circular path of same radii
the magnetic forces on them are same to each other
the kinetic energies of particles are same to each other
all of the above

3. The earths magnetic field at a certain point is 0.70 gauss. This field is to be annulled by the magnetic field at the centre of a circular conducting loop 5.0 cm in radius. The required current is about:
0.66 A
5.6 A
0.28 A
2.8 A

4. If an electron and proton having same momenta enter perpendicularly to a magnetic field then:
curved path of electron and proton will be same
(ignoring the sense of revolution)
they will move undeflected
path of proton is more curved

5. A charged particle enters a region of non-uniform field and eventually comes out of it. As it emerges its
speed is greater as compared to the speed at entry point
velocity remains unchanged velocity may change but
curved path of electron is more curved than that of proton
speed remain unchanged speed cannot be estimated as data is insufficient

6. A particle having positive charge is released from rest in an electric field acting horizontally and moves under the influence of both electric field and gravity Which one of the following quantities connected with the charge particles continuously increases with time?
Electric potential energy
Gravitational potential energy
Electrical charge
Kinetic energy

7. A charged particle placed in a uniform magnetic field experiences:
A force in the direction of the field
A force opposite to the direction of the field
A force perpendicular to the direction of the field
None

8. If the current is flowing clockwise in a circular coil the direction of lines of force inside the coil is:
towards you
away from you
towards the centre along the radius
away from the centre along the radius

9. A beam of protons is deflected side ways. Could this deflection be caused by:
magnetic field only
electric field only
either electric or magnetic field
both electric and magnetic fields

10. A positive charge is moving upwards in a magnetic field which is towards north. The particle will be deflected towards:
east
west
north
south

11. A current loop placed in a magnetic field because like a:
magnetic dipole
magnetic substance
magnetic pole
all are true

12. The strength of the magnetic field around a straight wire:
is same everywhere around the wire obeys inverse square law
is directly proportional to the square of the distance
from the wire
none of the above

13. As per Amperes law the line integral of the magnetic intensity around a closed path is equal to:
the charge enclosed
the current enclosed
the energy enclosed
the flux enclosed

14. A positive charge is released from the origin at a place where uniform electric field E and a uniform magnetic field B exist along the positive y-axis and positive z-axis respectively then:
initially the charged particle tends to move along positive z-axis
initially the charged particle tends to move along negative y-direction
initially the charged particle tends to move along positive y-direction
the charged particle moves in y-z plane

15. Two protons are moving with same velocity in magnetic field of same magnitude then:
magnetic force on protons may be zero
magnetic force on both must be same to each other magnetic force on both
may or may not be same to each other
both A and C are correct

16. When a charged particle moves in a magnetic field its KE always:
increases
magnetic force on both must be same to each other
remains constant increases or decreases
which depends on direction of projection of particle

17. The time period of a charged particle undergoing a circular motion in a uniform magnetic field is independent of its:
decreases
magnetic force on both
charge
magnetic induction

18. Imagine that you are seated in a room and there is a uniform magnetic field pointing vertically downwards in it. At the centre of the room an electron is projected horizontally with a certain speed. Discuss the speed and the path of the electron in this field.
Electron moves in anticlockwise path
Electron moves in clockwise path
Electron moves left wards
Electron moves right wards

19. If a current is passed through a spring then the spring will:
expand
compress
remain same
none of these

20. A charged particle moves in a magnetic field in a plane perpendicular to the magnetic field. The orbital magnetic moment of circulating charge is direction:
parallel to magnetic field
against the magnetic field
perpendicular to magnetic field
none of the above

21. 3.In a region steady and uniform electric and magnetic fields are present. These two fields are parallel to each other. A charged particle is released from rest in this region. The path of the particle will be a:
helix
straight line
ellipse
circle

22. Mark correct option or options
Electric field and magnetic field are basically independent
Electric field and magnetic field are two aspects of the electromagnetic field
Electric field and magnetic field may be produced by charge in rest
Both A and C are correct

23. A proton moving in a straight line enters a strong magnetic field along the field direction How will its path and velocity change?
Path is circular but speed constant
Path is same but velocity increase
Path is same and velocity remains constant
Path is same but motion is retarded

24. A long wire carries a current of 20 A along the axis of a solenoid the field due to the solenoid is 4 mT. The resultant field at a point 3 mm from the solenoid axis is:
1.33 mT
4.2 mT
2.1 mT
8.4 mT

25. A conducting loop carrying a current is placed in a non-uniform magnetic field perpendicular to the plane of loop. Then:
loop must experience force
loop may experience torque
loop must experience torque
none of the above

26. A uniform electric field and a uniform magnetic field are acting along the same direction in a certain region. If an electron is projected along the direction of the fields with a certain velocity then:
its velocity will decrease
its velocity will increase
it will turn towards right of directions of motion
it will turn towards left of direction of motion

27. The direction of magnetic field at a point due to an infinitely long wire carrying current is:
parallel to the current
antiparallel to the current
along the perpendicular drawn from a point on the wire
perpendicular to the plane containing the conductor and the point

28. If the p. d. between two plates separated by a distance d be V then electric field E is equal to
Vd
d / V
d / V
V/ d

29. A charged particle moves through a magnetic field in a direction perpendicular to it then
the speed of the particle remains unchanged
the direction of particle remains unchanged
acceleration remains unchanged
velocity remains unchanged

30. A length of wire carries a steady current. It is bent to form a circular coil of one turn only. The same length is now bent more sharply to give a double loop of smaller radius. The magnetic field at the centre caused by the same current is
A half of its first value
Unaltered
A quarter of its first value
Four times its first value

31. The magnetic induction at a point due to a long straight conductor carrying current is independent of
its length
the current coil
the distance from the given point
all of the above

32. A vertical straight conductor carries a current vertically upwards. A point P lies to the east of it at a it at the same distance. The magnetic field at P is
greater as at Q
same as at Q
less than at Q
greater or less than at Q depending upon the strength of the current

33. You are facing a coil through which a current I is passing in the clockwise direction. The face of the coil towards you is a
notth pole
monopole
dipole
south pole

34. Two infinitely long thin insulated straight wires lie in x-y plane along the x and y-axis respectively. Each wire carries a current I respectively in the positive X-direction and positive Y-direction. The magnetic field will be zero at all points on the straight line
y = x
y = - 2x
y = x -4
y = - x + 5

35. A bar magnet is oscillating in Earths magnetic field with a period T. What happens to its period and motion if its mass is quadrupled ?
Motion remains simple harmonic with time period = T / 2
Motion remains simple harmonic with time period = 2 T
Motion remains simple harmonic with time period = 4 T
Motion remains simple harmonic and period remains nearly constant

36. A charged particle moving at right angle to the uniform magnetic field follows
linear path
parabolic path
circular path
hyperbolic path

37. The direction of force on a conductor carrying current in a magnetic fields is given by
Flemings right hand rule
Fleming s left hand rule
Savart s rule
Laplace rule.

38. A sensitive magnetic instrument can be shielded very effectively from outside magnetic fields by placing it inside a box of
metal of high conductivity soft iron of high
permeability
wood
plastic material

39. To measure charge the galvanometer used is
an ammeter
ballistic galvanometer
voltmeter
moving coil galvanometer

40. A moving coil galvanometer used is
dead beat type
oscillatory
ballistic
None of these

41. The permeanility of a material is 0.7421. This material is
Diamagnetic
Paramagnetic
Ferromagnetic
None of these.

42. The restoring couple in the moving coil galvanometer is because of
magnetic field
material of the coil
twist produced in the suspension
current in the coil

43. The lines of force around an infinitely long conductor carrying current are
perpendicular to the conductor
inclined to the conductor
parallel to the conductor
concentric circles

44. The south pole of a magnetic is placed on the axis of circular coil carrying current in the clockwise direction . It experiences a force of
attraction
epulsion
neither attraction nor repulsion
both attraction and repulsion.

45. Argon Krypton Xenon Radon are the examples of
non-magnetics
ferromagnetics
paramagnetics
diamagnatics

46. Cosmic rays are said to be highly energetic protons hitting the earth on account of earths magnetic field. They should get deflected to
North
South
East
West

47. If the magnetic moment of the atoms of a substance is zero the substance is called
diamagnetic
paramagnetic
ferromagnetic
anti-ferromagnetic field

48. When a charged particle moves inside a transverse electric field the path traced out by it is
a circle
a straight line
elliptical
parabola.

49. A charged particle moving at right angle to the electric field follows
parabolic path
circular path
linear path
elliptical path

50. In dead beat galvanometer the frame on which coil is wound is
semi conductor
metallic
non-metallic
of phosphor bronze

51. If a long copper rod carries a direct current the magnetic field associated with the current will be
inside the rod only
outside the rod only
both inside and outside the rod
neither inside nor outside the rod.

52. The S-pole of a magnet is placed on the axis of a circular coil carrying current in ant-clockwise direction. It experiences a force of
attraction
repulsion
neither attraction nor repulsion
both attraction and repulsion

53. If proton are shot perpendicular toa magnetic field
Magnetic field will have no influence on the motion of protons
Protons will continue to move in the same direction but will gain momentum
Protons will continue to move in the opposite directions but will gain momentum
They will bend in an are of a circle.