-
question_answer1)
An iron rod of length L and magnetic moment M is bent in the form of a semicircle. Now its magnetic moment will be [CPMT 1984; MP Board 1986; NCERT 1975; MP PET/PMT 1988; EAMCET (Med.) 1995; Manipal MEE 1995;RPMT 1996; BHU 1995; MP PET 2002]
A)
\[M\] done
clear
B)
\[\frac{2M}{\pi }\] done
clear
C)
\[\frac{M}{\pi }\] done
clear
D)
\[M\pi \] done
clear
View Solution play_arrow
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question_answer2)
Unit of magnetic flux density (or magnetic induction) is [DPMT 1988;CPMT 1984, 78, 90; MP PMT 1992; MH CET 2004]
A)
Tesla done
clear
B)
Weber/metre2 done
clear
C)
Newton/ampere-metre done
clear
D)
All of the above done
clear
View Solution play_arrow
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question_answer3)
Magnetic intensity for an axial point due to a short bar magnet of magnetic moment M is given by [MP PET 1984; CPMT 1974; Pb. PMT 1999]
A)
\[\frac{{{\mu }_{0}}}{4\pi }\times \frac{M}{{{d}^{3}}}\] done
clear
B)
\[\frac{{{\mu }_{0}}}{4\pi }\times \frac{M}{{{d}^{2}}}\] done
clear
C)
\[\frac{{{\mu }_{0}}}{2\pi }\times \frac{M}{{{d}^{3}}}\] done
clear
D)
\[\frac{{{\mu }_{0}}}{2\pi }\times \frac{M}{{{d}^{2}}}\] done
clear
View Solution play_arrow
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question_answer4)
A magnet is placed in iron powder and then taken out, then maximum iron powder is at
A)
Some away from north pole done
clear
B)
Some away from south pole done
clear
C)
The middle of the magnet done
clear
D)
The end of the magnet done
clear
View Solution play_arrow
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question_answer5)
A magnet of magnetic moment M and pole strength m is divided in two equal parts, then magnetic moment of each part will be [MP Board 1985; MP PET 1984, 2000; NCERT 1974; AFMC 1996; MP PMT 2002; MH CET (Med.) 2001; CPMT 1983, 84; KCET 1994, 2001]
A)
\[M\] done
clear
B)
\[M/2\] done
clear
C)
\[M/4\] done
clear
D)
\[2M\] done
clear
View Solution play_arrow
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question_answer6)
Points A and B are situated along the extended axis of 2 cm long bar magnet at a distance x and 2x cm respectively. From the pole nearer to the points, the ratio of the magnetic field at A and B will be [EAMCET 1984; CPMT 1986]
A)
4 : 1 exactly done
clear
B)
4 : 1 approx. done
clear
C)
8 : 1 exactly done
clear
D)
8 : 1 approx. done
clear
View Solution play_arrow
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question_answer7)
If a magnet of pole strength m is divided into four parts such that the length and width of each part is half that of initial one, then the pole strength of each part will be
A)
\[m/4\] done
clear
B)
\[m/2\] done
clear
C)
\[m/8\] done
clear
D)
\[4m\] done
clear
View Solution play_arrow
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question_answer8)
The distance of two points on the axis of a magnet from its centre is 10 cm and 20 cm respectively. The ratio of magnetic intensity at these points is 12.5 : 1. The length of the magnet will be
A)
5 cm done
clear
B)
25 cm done
clear
C)
10 cm done
clear
D)
20 cm done
clear
View Solution play_arrow
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question_answer9)
Ratio of magnetic intensities for an axial point and a point on broad side-on position at equal distance d from the centre of magnet will be or The magnetic field at a distance d from a short bar magnet in longitudinal and transverse positions are in the ratio [CPMT 1978, 82; KCET 1998]
A)
1 : 1 done
clear
B)
2 : 3 done
clear
C)
2 : 1 done
clear
D)
3 : 2 done
clear
View Solution play_arrow
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question_answer10)
The magnetism of magnet is due to [JIPMER 1997]
A)
The spin motion of electron done
clear
B)
Earth done
clear
C)
Pressure of big magnet inside the earth done
clear
D)
Cosmic rays done
clear
View Solution play_arrow
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question_answer11)
The pole strength of a bar magnet is 48 ampere-metre and the distance between its poles is 25 cm. The moment of the couple by which it can be placed at an angle of 30o with the uniform magnetic intensity of flux density 0.15 Newton /ampere-metre will be
A)
12 Newton × metre done
clear
B)
18 Newton × metre done
clear
C)
0.9 Newton × metre done
clear
D)
None of the above done
clear
View Solution play_arrow
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question_answer12)
The magnetic field at a point x on the axis of a small bar magnet is equal to the field at a point y on the equator of the same magnet. The ratio of the distances of x and y from the centre of the magnet is [MP PMT 1990]
A)
\[{{2}^{-3}}\] done
clear
B)
\[{{2}^{-1/3}}\] done
clear
C)
\[{{2}^{3}}\] done
clear
D)
\[{{2}^{1/3}}\] done
clear
View Solution play_arrow
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question_answer13)
A magnet of magnetic moment 20 C.G.S. units is freely suspended in a uniform magnetic field of intensity 0.3 C.G.S. units. The amount of work done in deflecting it by an angle of 30o in C.G.S. units is [MP PET 1991]
A)
6 done
clear
B)
\[3\sqrt{3}\] done
clear
C)
\[3(2-\sqrt{3)}\] done
clear
D)
\[3\] done
clear
View Solution play_arrow
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question_answer14)
A bar magnet having centre O has a length of 4 cm. Point P1 is in the broad side-on and P2 is in the end side-on position with OP1 = OP2 = 10 metres. The ratio of magnetic intensities H at P1 and P2 is [MP PET 1990]
A)
\[{{H}_{1}}:{{H}_{2}}=16:100\] done
clear
B)
\[{{H}_{1}}:{{H}_{2}}=1:2\] done
clear
C)
\[{{H}_{1}}:{{H}_{2}}=2:1\] done
clear
D)
\[{{H}_{1}}:{{H}_{2}}=100:16\] done
clear
View Solution play_arrow
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question_answer15)
The magnetic field due to a short magnet at a point on its axis at distance X cm from the middle point of the magnet is 200 Gauss. The magnetic field at a point on the neutral axis at a distance X cm from the middle of the magnet is [CPMT 1971, 88; MP PET 1985]
A)
100 Gauss done
clear
B)
400 Gauss done
clear
C)
50 Gauss done
clear
D)
200 Gauss done
clear
View Solution play_arrow
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question_answer16)
Which of the following, the most suitable material for making permanent magnet is
A)
Steel done
clear
B)
Soft iron done
clear
C)
Copper done
clear
D)
Nickel done
clear
View Solution play_arrow
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question_answer17)
In the case of bar magnet, lines of magnetic induction [CPMT 1975; CBSE PMT 1990]
A)
Start from the north pole and end at the south pole done
clear
B)
Run continuously through the bar and outside done
clear
C)
Emerge in circular paths from the middle of the bar done
clear
D)
Are produced only at the north pole like rays of light from a bulb done
clear
View Solution play_arrow
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question_answer18)
A sensitive magnetic instrument can be shielded very effectively from outside magnetic fields by placing it inside a box of [CPMT 1974]
A)
Teak wood done
clear
B)
Plastic material done
clear
C)
Soft iron of high permeability done
clear
D)
A metal of high conductivity done
clear
View Solution play_arrow
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question_answer19)
The field due to a magnet at a distance R from the centre of the magnet is proportional to [MP PET 1996]
A)
\[{{R}^{2}}\] done
clear
B)
\[{{R}^{3}}\] done
clear
C)
\[1/{{R}^{2}}\] done
clear
D)
\[1/{{R}^{3}}\] done
clear
View Solution play_arrow
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question_answer20)
A)
Figure done
clear
B)
Figure done
clear
C)
Figure done
clear
D)
Figure done
clear
View Solution play_arrow
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question_answer21)
The figure below shows the north and south poles of a permanent magnet in which n turn coil of area of cross-section A is resting, such that for a current i passed through the coil, the plane of the coil makes an angle \[\theta \]with respect to the direction of magnetic field B. If the plane of the magnetic field and the coil are horizontal and vertical respectively, the torque on the coil will be [CPMT 1986, 88; DPMT 2002]
A)
\[\tau =niAB\cos \theta \] done
clear
B)
\[\tau =niAB\sin \theta \] done
clear
C)
\[\tau =niAB\] done
clear
D)
None of the above, since the magnetic field is radial done
clear
View Solution play_arrow
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question_answer22)
Points A and B are situated perpendicular to the axis of a 2cm long bar magnet at large distances X and 3X from its centre on opposite sides. The ratio of the magnetic fields at A and B will be approximately equal to [CPMT 1988]
A)
1 : 9 done
clear
B)
2 : 9 done
clear
C)
27 : 1 done
clear
D)
9 : 1 done
clear
View Solution play_arrow
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question_answer23)
Two short magnets with their axes horizontal and perpendicular to the magnetic meridian are placed with their centres 40 cm east and 50 cm west of magnetic needle. If the needle remains undeflected, the ratio of their magnetic moments \[{{M}_{1}}:{{M}_{2}}\] is [MP PET 1990]
A)
4 : 5 done
clear
B)
16 : 25 done
clear
C)
64 : 125 done
clear
D)
\[2:\sqrt{5}\] done
clear
View Solution play_arrow
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question_answer24)
If a bar magnet of magnetic moment M is freely suspended in a uniform magnetic field of strength B, the work done in rotating the magnet through an angle\[\theta \] is [AFMC 1997; MNR 1998; RPET 1999; MP PMT 1989, 96, 99; MP PET 1984, 89, 2000; UPSEAT 1999, 2000, 05]
A)
\[MB(1-\sin \theta )\] done
clear
B)
\[MB\sin \theta \] done
clear
C)
\[MB\cos \theta \] done
clear
D)
\[MB(1-\cos \theta )\] done
clear
View Solution play_arrow
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question_answer25)
Two small bar magnets are placed in a line with like poles facing each other at a certain distance d apart. If the length of each magnet is negligible as compared to d, the force between them will be inversely proportional to [CPMT 1971; NCERT 1971; MP PMT 1992]
A)
\[d\] done
clear
B)
\[{{d}^{2}}\] done
clear
C)
\[\frac{1}{{{d}^{2}}}\] done
clear
D)
\[{{d}^{4}}\] done
clear
View Solution play_arrow
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question_answer26)
A magnet of magnetic moment M is situated with its axis along the direction of a magnetic field of strength B. The work done in rotating it by an angle of 180o will be [MP PMT 1985; MP PET 1997]
A)
\[-MB\] done
clear
B)
\[+MB\] done
clear
C)
0 done
clear
D)
\[+2MB\] done
clear
View Solution play_arrow
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question_answer27)
A long magnet is cut in two parts in such a way that the ratio of their lengths is 2 : 1. The ratio of pole strengths of both the section is [CPMT 1986]
A)
Equal done
clear
B)
In the ratio of 2 : 1 done
clear
C)
In the ratio of 1 : 2 done
clear
D)
In the ratio of 4 : 1 done
clear
View Solution play_arrow
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question_answer28)
A bar magnet of length 10 cm and having the pole strength equal to 10?3 weber is kept in a magnetic field having magnetic induction equal to \[4\pi \times {{10}^{-3}}\]Tesla. It makes an angle of 30o with the direction of magnetic induction. The value of the torque acting on the magnet is [MP PMT 1993]
A)
\[2\pi \times {{10}^{-7}}N\times m\] done
clear
B)
\[2\pi \times {{10}^{-5}}N\times m\] done
clear
C)
\[0.5N\times m\] done
clear
D)
\[0.5\times {{10}^{2}}N\times m\] (\[{{\mu }_{0}}=4\pi \times {{10}^{-7}}weber/amp\times m\]) done
clear
View Solution play_arrow
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question_answer29)
Magnetic field intensity is defined as [MP PET 1993]
A)
Magnetic moment per unit volume done
clear
B)
Magnetic induction force acting on a unit magnetic pole done
clear
C)
Number of lines of force crossing per unit area done
clear
D)
Number of lines of force crossing per unit volume done
clear
View Solution play_arrow
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question_answer30)
If the magnetic flux is expressed in weber, then magnetic induction can be expressed in [CPMT 1974, 77, 83, 86, 87; MP PET 1989]
A)
Weber/m2 done
clear
B)
Weber/m done
clear
C)
Weber-m done
clear
D)
Weber-m2 done
clear
View Solution play_arrow
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question_answer31)
A magnetic needle is kept in a non-uniform magnetic field. It experiences [MP PMT 1987; IIT 1982; Kerala PET 2002; AMU 1999; AIEEE 2005]
A)
A force and a torque done
clear
B)
A force but not a torque done
clear
C)
A torque but not a force done
clear
D)
Neither a torque nor a force done
clear
View Solution play_arrow
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question_answer32)
The magnetic induction in air at a distance d from an isolated point pole of strength m unit will be [MNR 1987; CPMT 1991; MP PET 1995; AMU 1999; J & K CET 2005]
A)
\[\frac{m}{d}\] done
clear
B)
\[\frac{m}{{{d}^{2}}}\] done
clear
C)
\[md\] done
clear
D)
\[m{{d}^{2}}\] done
clear
View Solution play_arrow
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question_answer33)
A magnetic needle lying parallel to a magnetic field requires W units of work to turn it through 60°. The torque required to maintain the needle in this position will be [KCET 1994; MNR 1991; MP PET 1996; [AIEEE 2003; UPSEAT 2000; BHU 2004; Pb PET 2004]
A)
\[\sqrt{3}\,W\] done
clear
B)
W done
clear
C)
\[\frac{\sqrt{3}}{2}W\] done
clear
D)
2W done
clear
View Solution play_arrow
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question_answer34)
A long magnetic needle of length 2L, magnetic moment M and pole strength m units is broken into two pieces at the middle. The magnetic moment and pole strength of each piece will be [NCERT 1983; DPMT 1987]
A)
\[\frac{M}{2},\frac{m}{2}\] done
clear
B)
\[M,\frac{m}{2}\] done
clear
C)
\[\frac{M}{2},m\] done
clear
D)
\[M,m\] done
clear
View Solution play_arrow
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question_answer35)
Two identical thin bar magnets each of length l and pole strength m are placed at right angle to each other with north pole of one touching south pole of the other. Magnetic moment of the system is [MNR 1981; MP PET 2002]
A)
ml done
clear
B)
2ml done
clear
C)
\[\sqrt{2}ml\] done
clear
D)
\[\frac{1}{2}ml\] done
clear
View Solution play_arrow
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question_answer36)
Magnetic induction is a [AFMC 1986]
A)
Scalar quantity done
clear
B)
Vector quantity done
clear
C)
Both (a) and (b) done
clear
D)
None of the above done
clear
View Solution play_arrow
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question_answer37)
What happens to the force between magnetic poles when their pole strength and the distance between them are both doubled [CPMT 1978, 80, 84, 85; MP PET 2005]
A)
Force increases to two times the previous value done
clear
B)
No change done
clear
C)
Force decreases to half the previous value done
clear
D)
Force increases to four times the previous value done
clear
View Solution play_arrow
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question_answer38)
Force between two unit pole strength placed at a distance of one metre is [CPMT 1987]
A)
1 N done
clear
B)
\[\frac{{{10}^{-7}}}{4\pi }N\] done
clear
C)
\[{{10}^{-7\,}}\,N\] done
clear
D)
\[4\pi \times {{10}^{-7}}N\] done
clear
View Solution play_arrow
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question_answer39)
A small bar magnet of moment M is placed in a uniform field H. If magnet makes an angle of 30° with field, the torque acting on the magnet is [CPMT 1989]
A)
MH done
clear
B)
\[\frac{MH}{2}\] done
clear
C)
\[\frac{MH}{3}\] done
clear
D)
\[\frac{MH}{4}\] done
clear
View Solution play_arrow
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question_answer40)
If a hole is made at the centre of a bar magnet, then its magnetic moment will
A)
Increase done
clear
B)
Decrease done
clear
C)
Not change done
clear
D)
None of these done
clear
View Solution play_arrow
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question_answer41)
The small magnets each of magnetic moment 10 A-m2 are placed end-on position 0.1m apart from their centres. The force acting between them is [MNR 1994]
A)
\[0.6\times {{10}^{7}}N\] done
clear
B)
\[0.06\times {{10}^{7}}N\] done
clear
C)
\[0.6N\] done
clear
D)
\[0.06N\] done
clear
View Solution play_arrow
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question_answer42)
Magnetic lines of force [MP PET 1994]
A)
Always intersect done
clear
B)
Are always closed done
clear
C)
Tend to crowd far away from the poles of magnet done
clear
D)
Do not pass through vacuum done
clear
View Solution play_arrow
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question_answer43)
Rate of change of torque \[\tau \] with deflection\[\theta \]is maximum for a magnet suspended freely in a uniform magnetic field of induction B, when [MP PET 1994]
A)
\[\theta =0{}^\circ \] done
clear
B)
\[\theta =45{}^\circ \] done
clear
C)
\[\theta =60{}^\circ \] done
clear
D)
\[\theta =90{}^\circ \] done
clear
View Solution play_arrow
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question_answer44)
A magnet of magnetic moment M is rotated through 360° in a magnetic field H, the work done will be [KCET 1998; MP PMT 1994; Roorkee 2000]
A)
MH done
clear
B)
2MH done
clear
C)
\[2\pi MH\] done
clear
D)
Zero done
clear
View Solution play_arrow
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question_answer45)
The direction of line of magnetic field of bar magnet is [AFMC 1995]
A)
From south pole to north pole done
clear
B)
From north pole to south pole done
clear
C)
Across the bar magnet done
clear
D)
From south pole to north pole inside the magnet and from north pole to south pole outside the magnet done
clear
View Solution play_arrow
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question_answer46)
The work done in turning a magnet of magnetic moment 'M' by an angle of 90° from the meridian is 'n' times the corresponding work done to turn it through an angle of 60°, where 'n' is given by [CBSE PMT 1995; MP PET 2003]
A)
1/2 done
clear
B)
2 done
clear
C)
1/4 done
clear
D)
1 done
clear
View Solution play_arrow
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question_answer47)
Force between two identical bar magnets whose centres are r metre apart is 4.8 N, when their axes are in the same line. If separation is increased to 2r, the force between them is reduced to [AIIMS 1995]
A)
2.4N done
clear
B)
1.2N done
clear
C)
0.6N done
clear
D)
0.3N done
clear
View Solution play_arrow
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question_answer48)
A bar magnet of magnetic moment 104J/T is free to rotate in a horizontal plane. The work done in rotating the magnet slowly from a direction parallel to a horizontal magnetic field of 4×10?5 T to a direction 60° from the field will be [MP PET 1995]
A)
0.2 J done
clear
B)
2.0 J done
clear
C)
4.18 J done
clear
D)
2 × 102 J done
clear
View Solution play_arrow
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question_answer49)
Magnetic lines of force due to a bar magnet do not intersect because [MP PMT 1995]
A)
A point always has a single net magnetic field done
clear
B)
The lines have similar charges and so repel each other done
clear
C)
The lines always diverge from a single point done
clear
D)
The lines need magnetic lenses to be made to intersect done
clear
View Solution play_arrow
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question_answer50)
The unit of magnetic moment is [MP PET 1996; AMU 2000; MP PMT 1995, 2002]
A)
Wb/m done
clear
B)
\[Wb.{{m}^{2}}\] done
clear
C)
A.m done
clear
D)
\[A.{{m}^{2}}\] done
clear
View Solution play_arrow
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question_answer51)
The dipole moment of a short bar magnet is 1.25 A-m2. The magnetic field on its axis at a distance of 0.5metre from the centre of the magnet is
A)
\[1.0\times {{10}^{-4}}Newton/amp-meter\] done
clear
B)
\[4\times {{10}^{-2}}Newton/amp-metre\] done
clear
C)
\[2\times {{10}^{-6}}Newton/amp-metre\] done
clear
D)
\[6.64\times {{10}^{-8}}Newton/amp-metre\] done
clear
View Solution play_arrow
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question_answer52)
A permanent magnet [MP PET 1996]
A)
Attracts all substances done
clear
B)
Attracts only magnetic substances done
clear
C)
Attracts magnetic substances and repels all non-magnetic substances done
clear
D)
Attracts non-magnetic substances and repels magnetic substances done
clear
View Solution play_arrow
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question_answer53)
Two equal bar magnets are kept as shown in the figure. The direction of resultant magnetic field, indicated by arrow head at the point P is (approximately)
A)
B)
C)
D)
View Solution play_arrow
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question_answer54)
The S.I. unit of magnetic permeability is [MP PET 1997]
A)
\[A{{m}^{-1}}\] done
clear
B)
\[Am\] done
clear
C)
\[Henry\,{{m}^{-1}}\] done
clear
D)
No unit, it is a dimensionless number done
clear
View Solution play_arrow
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question_answer55)
A short bar magnet placed with its axis at 30° with a uniform external magnetic field of 0.16 Tesla experiences a torque of magnitude 0.032 Joule. The magnetic moment of the bar magnet will be [MP PMT 1997; UPSEAT 2004]
A)
0.23 Joule/Tesla done
clear
B)
0.40 Joule/Tesla done
clear
C)
0.80Joule/Tesla done
clear
D)
Zero done
clear
View Solution play_arrow
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question_answer56)
The magnetic field to a small magnetic dipole of magnetic moment M, at distance r from the centre on the equatorial line is given by (in M.K.S. system) [MP PMT/PET 1998]
A)
\[\frac{{{\mu }_{0}}}{4\pi }\times \frac{M}{{{r}^{2}}}\] done
clear
B)
\[\frac{{{\mu }_{0}}}{4\pi }\times \frac{M}{{{r}^{3}}}\] done
clear
C)
\[\frac{{{\mu }_{0}}}{4\pi }\times \frac{2M}{{{r}^{2}}}\] done
clear
D)
\[\frac{{{\mu }_{0}}}{4\pi }\times \frac{2M}{{{r}^{3}}}\] done
clear
View Solution play_arrow
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question_answer57)
The incorrect statement regarding the lines of force of the magnetic field B is [MP PET 1999]
A)
Magnetic intensity is a measure of lines of force passing through unit area held normal to it done
clear
B)
Magnetic lines of force form a close curve done
clear
C)
Inside a magnet, its magnetic lines of force move from north pole of a magnet towards its south pole done
clear
D)
Due to a magnet magnetic lines of force never cut each other done
clear
View Solution play_arrow
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question_answer58)
A straight wire carrying current i is turned into a circular loop. If the magnitude of magnetic moment associated with it in M.K.S. unit is M, the length of wire will be [MP PET 1999]
A)
\[4\pi iM\] done
clear
B)
\[\sqrt{\frac{4\pi M}{i}}\] done
clear
C)
\[\sqrt{\frac{4\pi i}{M}}\] done
clear
D)
\[\frac{M\pi }{4i}\] done
clear
View Solution play_arrow
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question_answer59)
A bar magnet of magnetic moment \[\overrightarrow{M}\] is placed in a magnetic field of induction \[\overrightarrow{B}\]. The torque exerted on it is [EAMCET (Engg.) 1995; CBSE PMT 1999; BHU 2003; CPMT 2004; MP PMT 2001, 05]
A)
\[\overrightarrow{M}.\overrightarrow{B\,}\] done
clear
B)
? \[\overrightarrow{M}.\overrightarrow{B\,}\] done
clear
C)
\[\overrightarrow{M}\times \overrightarrow{B\,}\] done
clear
D)
\[\overrightarrow{B\,}\times \overrightarrow{M}\] done
clear
View Solution play_arrow
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question_answer60)
For protecting a sensitive equipment from the external magnetic field, it should be [KCET 1993; CBSE PMT 1998]
A)
Placed inside an aluminium cane done
clear
B)
Placed inside an iron cane done
clear
C)
Wrapped with insulation around it when passing current through it done
clear
D)
Surrounded with fine copper sheet done
clear
View Solution play_arrow
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question_answer61)
If a piece of metal was thought to be magnet, which one of the following observations would offer conclusive evidence [KCET 1994]
A)
It attracts a known magnet done
clear
B)
It repels a known magnet done
clear
C)
Neither (a) nor (b) done
clear
D)
It attracts a steel screw driver done
clear
View Solution play_arrow
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question_answer62)
The magnet can be completely demagnetized by [KCET 1994]
A)
Breaking the magnet into small pieces done
clear
B)
Heating it slightly done
clear
C)
Droping it into ice cold water done
clear
D)
A reverse field of appropriate strength done
clear
View Solution play_arrow
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question_answer63)
A current loop placed in a magnetic field behaves like a [AFMC 1994]
A)
Magnetic dipole done
clear
B)
Magnetic substance done
clear
C)
Magnetic pole done
clear
D)
All are true done
clear
View Solution play_arrow
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question_answer64)
A magnet when placed perpendicular to a uniform field of strength \[{{10}^{-4}}Wb/{{m}^{2}}\] experiences a maximum couple of moment\[4\times {{10}^{-5}}N/m.\]. What is its magnetic moment [Bihar MEE 1995]
A)
\[0.4A\times {{m}^{2}}\] done
clear
B)
\[0.2A\times {{m}^{2}}\] done
clear
C)
\[0.16A\times {{m}^{2}}\] done
clear
D)
\[0.04A\times {{m}^{2}}\] (e) \[0.06A\times {{m}^{2}}\] done
clear
View Solution play_arrow
-
question_answer65)
Weber/m2 is equal to [CPMT 1985; AFMC 1997]
A)
Volt done
clear
B)
Henry done
clear
C)
Tesla done
clear
D)
All of these done
clear
View Solution play_arrow
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question_answer66)
Two magnets, each of magnetic moment ?M? are placed so as to form a cross at right angles to each other. The magnetic moment of the system will be [AFMC 1999; Pb PET 2001]
A)
2 M done
clear
B)
\[\sqrt{2}\,M\] done
clear
C)
0.5 M done
clear
D)
M done
clear
View Solution play_arrow
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question_answer67)
Two like magnetic poles of strength 10 and 40 SI units are separated by a distance 30 cm. The intensity of magnetic field is zero on the line joining them [JIPMER 1999]
A)
At a point 10 cm from the stronger pole done
clear
B)
At a point 20 cm from the stronger pole done
clear
C)
At the mid-point done
clear
D)
At infinity done
clear
View Solution play_arrow
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question_answer68)
If a magnet of length 10 cm and pole strength 40 A-m is placed at an angle of 45o in an uniform induction field of intensity 2 ´ 10?4 T, the couple acting on it is [Pb. PMT 1999; MH CET (Med.) 1999]
A)
0.5656 ´ 10?4 N-m done
clear
B)
0.5656 ´ 10?3 N-m done
clear
C)
0.656 ´ 10?4 N-m done
clear
D)
0.656 ´ 10?5 N-m done
clear
View Solution play_arrow
-
question_answer69)
The intensity of magnetic field is H and moment of magnet is M. The maximum potential energy is [Pb. PMT 1999; MH CET (Med.) 1999]
A)
MH done
clear
B)
2 MH done
clear
C)
3 MH done
clear
D)
4 MH done
clear
View Solution play_arrow
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question_answer70)
A bar magnet of magnetic moment 200 A-m2 is suspended in a magnetic field of intensity 0.25 N/A-m. The couple required to deflect it through 30o is [AFMC 1999; Pb. PET 2000]
A)
50 N-m done
clear
B)
25 N-m done
clear
C)
20 N-m done
clear
D)
15 N-m done
clear
View Solution play_arrow
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question_answer71)
Two similar bar magnets P and Q, each of magnetic moment M, are taken, If P is cut along its axial line and Q is cut along its equatorial line, all the four pieces obtained have [EAMCET (Engg.) 2000]
A)
Equal pole strength done
clear
B)
Magnetic moment \[\frac{M}{4}\] done
clear
C)
Magnetic moment \[\frac{M}{2}\] done
clear
D)
Magnetic moment M done
clear
View Solution play_arrow
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question_answer72)
A magnet of magnetic moment \[50\,\hat{i}\,A\text{-}{{m}^{2}}\] is placed along the x-axis in a magnetic field \[\overrightarrow{B}=(0.5\,\hat{i}+3.0\hat{j})\,T.\] The torque acting on the magnet is [MP PMT 2000]
A)
175 \[\hat{k}\,\,N\text{-}m\] done
clear
B)
150 \[\hat{k}\,\,N\text{-}m\] done
clear
C)
75 \[\hat{k}\,\,N\text{-}m\] done
clear
D)
\[25\sqrt{37}\,\hat{k}\,\,N\text{-}m\] done
clear
View Solution play_arrow
-
question_answer73)
A bar magnet is held perpendicular to a uniform magnetic field. If the couple acting on the magnet is to be halved by rotating it, then the angle by which it is to be rotated is [CBSE PMT 2000]
A)
30o done
clear
B)
45o done
clear
C)
60o done
clear
D)
90o done
clear
View Solution play_arrow
-
question_answer74)
There is no couple acting when two bar magnets are placed coaxially separated by a distance because [EAMCET (Engg.) 2000]
A)
There are no forces on the poles done
clear
B)
The forces are parallel and their lines of action do not coincide done
clear
C)
The forces are perpendicular to each other done
clear
D)
The forces act along the same line done
clear
View Solution play_arrow
-
question_answer75)
A bar magnet of magnetic moment 3.0 A-m2 is placed in a uniform magnetic induction field of 2 ´ 10?5 T. If each pole of the magnet experiences a force of 6 ´ 10?4 N, the length of the magnet is [EAMCET (Med.) 2000]
A)
0.5 m done
clear
B)
0.3 m done
clear
C)
0.2 m done
clear
D)
0.1 m done
clear
View Solution play_arrow
-
question_answer76)
A bar magnet when placed at an angle of 30o to the direction of magnetic field induction of 5 ´ 10?2 T, experiences a moment of couple 25 ´ 10?6 N-m. If the length of the magnet is 5 cm its pole strength is [EAMCET (Med.) 2000]
A)
2 ´ 10?2 A-m done
clear
B)
5 ´ 10?2 A-m done
clear
C)
2 A-m done
clear
D)
5 A-m done
clear
View Solution play_arrow
-
question_answer77)
Two lines of force due to a bar magnet [MP PMT 2002]
A)
Intersect at the neutral point done
clear
B)
Intersect near the poles of the magnet done
clear
C)
Intersect on the equatorial axis of the magnet done
clear
D)
Do not intersect at all done
clear
View Solution play_arrow
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question_answer78)
The ultimate individual unit of magnetism in any magnet is called [MP PET 2002; J & K CET 2004]
A)
North pole done
clear
B)
South pole done
clear
C)
Dipole done
clear
D)
Quadrupole done
clear
View Solution play_arrow
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question_answer79)
The magnetic field lines due to a bar magnet are correctly shown in [IIT-JEE (Screening) 2002]
A)
B)
C)
D)
View Solution play_arrow
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question_answer80)
The magnetic lines of force inside a bar magnet [AIEEE 2003]
A)
Are from south-pole to north-pole of the magnet done
clear
B)
Are from north-pole to south-pole of the magnet done
clear
C)
Do not exist done
clear
D)
Depend upon the area of cross-section of the bar magnet done
clear
View Solution play_arrow
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question_answer81)
If a magnet is hanged with its magnetic axis then it stops in [AFMC 2003]
A)
Magnetic meridian done
clear
B)
Geometric meridian done
clear
C)
Angle of dip done
clear
D)
None of these done
clear
View Solution play_arrow
-
question_answer82)
The work done in rotating a magnet of magnetic moment 2 A-m2 in a magnetic field of 5 ´ 10?3 T from the direction along the magnetic field to opposite direction to the magnetic field, is [MP PET 2003]
A)
Zero done
clear
B)
2 ´ 10?2 J done
clear
C)
10?2 J done
clear
D)
10 J done
clear
View Solution play_arrow
-
question_answer83)
The torque on a bar magnet due to the earth's magnetic field is maximum when the axis of the magnet is [MP PMT 2004]
A)
Perpendicular to the field of the earth done
clear
B)
Parallel to the vertical component of the earth's field done
clear
C)
At an angle of 33o with respect to the N-S direction done
clear
D)
Along the North-South (N-S) direction done
clear
View Solution play_arrow
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question_answer84)
Magnetic dipole moment is a [AFMC 2004]
A)
Scalar quantity done
clear
B)
Vector quantity done
clear
C)
Constant quantity done
clear
D)
None of these done
clear
View Solution play_arrow
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question_answer85)
A bar magnet of length 3 cm has points A and B along its axis at distances of 24 cm and 48 cm on the opposite sides. Ratio of magnetic fields at these points will be [DPMT 2004]
A)
8 done
clear
B)
\[1/2\,\,\sqrt{2}\] done
clear
C)
3 done
clear
D)
4 done
clear
View Solution play_arrow
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question_answer86)
A magnet of magnetic moment \[2\,J\,{{T}^{-1}}\] is aligned in the direction of magnetic field of 0.1 T. What is the net work done to bring the magnet normal to the magnetic field [DCE 2004]
A)
0.1 J done
clear
B)
0.2 J done
clear
C)
1 J done
clear
D)
2 J done
clear
View Solution play_arrow
-
question_answer87)
The magnetic moment of a magnet of length 10 cm and pole strength 4.0 Am will be [DPMT 2003]
A)
\[0.4\,\,A{{m}^{2}}\] done
clear
B)
\[1.6\,\,A{{m}^{2}}\] done
clear
C)
\[20\,\,A{{m}^{2}}\] done
clear
D)
\[8.0\,\,A{{m}^{2}}\] done
clear
View Solution play_arrow
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question_answer88)
The effective length of a magnet is 31.4 cm and its pole strength is 0.5 Am. The magnetic moment, if it is bent in the form of a semicircle will be [DPMT 2003]
A)
\[0.1\,\,A{{m}^{2}}\] done
clear
B)
\[0.01\,\,A{{m}^{2}}\] done
clear
C)
\[0.2\,\,A{{m}^{2}}\] done
clear
D)
\[1.2\,\,A{{m}^{2}}\] done
clear
View Solution play_arrow
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question_answer89)
The magnetic potential at a point on the axial line of a bar magnet of dipole moment M is V. What is the magnetic potential due to a bar magnet of dipole moment \[\frac{M}{4}\] at the same point [MH CET 2004]
A)
\[4\,V\] done
clear
B)
\[2\,V\] done
clear
C)
\[\frac{V}{2}\] done
clear
D)
\[\frac{V}{4}\] done
clear
View Solution play_arrow
-
question_answer90)
A small bar magnet has a magnetic moment 1.2 A-m2. The magnetic field at a distance 0.1 m on its axis will be : (m0 = 4p ´ 10?7 T-m/A) [BHU 2003]
A)
1.2 ´ 10?4 T done
clear
B)
2.4 ´ 10?4 T done
clear
C)
2.4 ´ 104 T done
clear
D)
1.2 ´ 104 T done
clear
View Solution play_arrow
-
question_answer91)
Two identical short bar magnets, each having magnetic moment of 10 Am2, are arranged such that their axial lines are perpendicular to each other and their centres be along the same straight line in a horizontal plane. If the distance between their centres is 0.2 m, the resultant magnetic induction at a point midway between them is \[({{\mu }_{0}}=4\pi \times {{10}^{-7}}H{{m}^{-1}})\] [EAMCET 2005]
A)
\[\sqrt{2}\times {{10}^{-7}}\] Tesla done
clear
B)
\[\sqrt{5}\times {{10}^{-7}}\] Tesla done
clear
C)
\[\sqrt{2}\times {{10}^{-3}}\] Tesla done
clear
D)
\[\sqrt{5}\times {{10}^{-3}}\] Tesla done
clear
View Solution play_arrow
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question_answer92)
A magnet of length 0.1 m and pole strength \[{{10}^{-4}}A.m.\] is kept in a magnetic field of \[30\,Wb/{{m}^{2}}\] at an angle 30°. The couple acting on it is ??? \[\times {{10}^{-4}}Nm.\] [MP PET 2005]
A)
7.5 done
clear
B)
3.0 done
clear
C)
1.5 done
clear
D)
6.0 done
clear
View Solution play_arrow
done
clear
done
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done
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done
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done
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done
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done
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done
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