Q.1.
Domain formation is the necessary feature of ..... [ GUJCET 2007]
-
55%
a) ferromagnetism
-
20%
b) paramagnetism
-
7%
c) diamagnetism
-
18%
d) All of these
Q.2.
A steel wire of length l has a magnetic moment M. It is then bent into a semicircular arc. the new magnetic moment is [ BHU 1995]
-
16%
a) M
-
58%
b) 2M /π
-
14%
c)M/l
-
12%
d)M×l
Q.3.
A bar magnet of magnetic moment 200 Am2 suspended in a magnetic field of intensity 0.25 N/Am. The couple required to deflect it through 30° is .. [ AFMC 2011]
-
15%
a) 15Nm
-
26%
b) 30Nm
-
54%
c) 25Nm
-
5%
d) 45Nm
Q.4.
If a diamagnetic substance is brought near the north or south pole of a bar magnet, is ... [ CBSE-PMT 2009]
-
16%
a) repelled by the north pole and attracted by the south pole
-
22%
b) attracted by the north and repelled by the south pole
-
19%
c) attracted by both the poles
-
43%
d) repelled by both the poles
Q.5.
Current 'i' is flowing in a coil of area and number of turns N, then magnetic moment of the coil, M is ... [ CBSE-PMT 2001]
-
66%
a)NiA
-
9%
b) Ni /A
-
9%
c)Ni/ √A
-
17%
d)N2Ai
Q.6.
The magnetic moment of a diamagnetic atom is ... [ CBSE-PMT 2010]
-
56%
a) equal to zero
-
19%
b) much greater than one
-
8%
c)1
-
17%
d)between zero and one
Q.7.
Above Curie temperature... [ CBSE-PMT 2006]
-
22%
a) a paramagnetic substance becomes diamagnetic
-
11%
b) a diamagnetic substance becomes paramagnetic
-
22%
c)a paramagnetic substance becomes ferromagnetic
-
44%
d)a ferromagnetic substance becomes paramagnetic.
Q.8.
A short bar magnet of magnetic moment 0.4JT-1 is placed in a uniform magnetic field of 0.16T. The magnet is in stable equilibrium when the potential energy is ... [ CBSE-PMT 2011]
-
21%
a)-0.64J
-
32%
b) zero
-
11%
c)-0.082J
-
36%
d) -0.064J
Q.9.
For protecting a sensitive equipment from the external electric arc, it should be... [ CBSE-PMT 1998]
-
28%
a) wrapped with insulation around it when a current is passing through it.
-
48%
b) placed inside an iron can
-
7%
c)surrounded with fine copper sheet
-
17%
d)placed inside the aluminum can
Q.10.
bar magnet of magnetic moment 200 A-m2 is suspended in a magnetic field of intensity 0.25N/Am. The couple required to deflect it through 30° is ...[ AFMC 1999]
-
16%
a)15 N-m
-
12%
b) 20N-m
-
68%
c)25 N-m
-
4%
d)50 N-m
Q.11.
If the magnetic dipole is rotated through the angle θ with respect to the direction of H, then work done will be..[ AFMC 1997]
-
48%
a) MH(1-cosθ)
-
29%
b) MH cosθ
-
14%
c)MH(1-sinθ)
-
10%
d)MH sinΘ
Explanation
Q.12.
A diamagnetic substance is placed in a magnetic field of a bar magnet Then it is ...[ AFMC 2003]
-
77%
a) repelled by magnet
-
5%
b) attracted by magnet
-
5%
c)attracted by S-pole and repelled by N-pole
-
14%
d)attracted by S-pole and repelled by N-pole
Q.13.
At which place, earth's magnetic field becomes horizontal? [ AFMC 2004]
-
26%
a) Magnetic pole
-
26%
b) Geographical pole
-
22%
c) Magnetic meridian
-
26%
d) Magnetic equator
Q.14.
The substances in which the magnetic moment of a single atom is not zero, is called as [ AFMC 1999]
-
39%
a)ferromagnetic
-
43%
b) paramagnetic
-
17%
c)ferromagnetic
-
0%
d)diamagnetic
Q.15.
At a certain place, the horizontal component of earth's magnetic field is √3 time of its vertical component, the angle of dip at that place is .. [ AFMC 2000]
-
5%
a) 75°
-
74%
b) 60°
-
0%
c)45°
-
21%
d)30°
Q.16.
Curie temperature of iron is the temperature below which it is ...[ AFMC 2002]
-
24%
a) super conducting
-
67%
b) ferromagnetic
-
10%
c)diamagnetic
-
0%
d)radioactive
Q.17.
The work done in turning a magnetic moment M by an angle of 90° from the meridian is an times the corresponding work done to turn through an angle of 60°, where an is given by .. [ AFMC 2002]
-
17%
a) 1
-
50%
b) 1/2
-
6%
c) 4
-
28%
d) 2
Q.18.
) In which type of material the magnetic susceptibility does not depend on temperature [ AFMC 2007]
-
55%
a)diamagnetic
-
15%
b) paramagnetic
-
15%
c)Ferromagnetic
-
15%
d)Ferrite
Q.19.
Angle between magnetic meridian and geographical meridian is called..[ AFMC 2009]
-
32%
a) angle of dip
-
37%
b) angle of declination
-
5%
c)angle of depression
-
26%
d)both(a) and (b)
Q.20.
The magnetic lines of forces inside a bar magnet.. [ AFMC 2009]
-
11%
a) are from north pole to south pole of the magnet
-
5%
b) do not exist
-
16%
c)depend upon the area of cross-section of bar magnet
-
68%
d)are from south pole to north pole of the magnet
Q.21.
The angle of dip is θ at a place where the horizontal and vertical component of the earth's magnetic field is equal. The value of θ is : [ SCRA 1994]
-
29%
a) 0°
-
21%
b) 30°
-
36%
c)45°
-
14%
d)60°
Q.22.
Nickel shows ferromagnetic property at room temperature. if the temperature is increased beyond Curie temperature, then it will show... [ CBSE-PMT 2007]
-
11%
a) anti ferromagnetism
-
16%
b) no magnetic property
-
5%
c)diamagnetism
-
68%
d)para magnetism
Q.23.
If the magnetic dipole moment of an atom of diamagnetic material and ferromagnetic material are denoted by µd, µp, µf respectively, then ... [ CSBE-PMT 2005]
-
61%
a) µd=0 andµp ≠ µp
-
11%
b) µd ≠ 0 andµp=0
-
22%
c) µp=0 andµf ≠ 0
-
6%
d) µd ≠ 0 and µf ≠ 0
Q.24.
Electromagnets are made of soft iron because soft iron have ... [ CBSE-PMT 2010]
-
14%
a)low retentivity and high coercivity
-
19%
b) high retentivity and high coercivity
-
52%
c)low retentivity and low coercivity
-
14%
d)high retentivity and low coercivity
Q.25.
A vibrating magnetometer placed in magnetic meridian has a small bar magnet. The magnet executes oscillations with time period of 2 sec in earth's horizontal magnetic field of 24 microtesla.When a horizontal field of 6 microtesla is produced opposite to the earth's field by placing a current carrying wire, the new time period of magnet will be ...[ CBSE-PMT 2010]
-
12%
a) 1 s
-
44%
b) 2s
-
12%
c)3s
-
31%
d)4s
Explanation
Q.26.
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.. [ CBSE-PMT 2011] (i) A is freely repelled(ii) B is feebly attracted(iii) C is strongly attracted(iv) D remains unaffectedWhich one of the following is true?
-
78%
a) B is of a paramagnetic material
-
17%
b) C is of a diamagnetic material
-
6%
c)D is of a ferromagnetic material
-
0%
d)A is of a non-magnetic material
Q.27.
A bar magnet is oscillating in earth's magnetic field with a period T. What happens to its period of motion, if its mass is quadrupled [ CBSE-PMT 1994]
-
20%
a) motion remains simple harmonic with new period=T/2
-
33%
b) motion remains simple harmonic with new period=2T
-
33%
c) motion remains simple harmonic with new period=4T
-
13%
d) motion remains simple harmonic and the period stays nearly constant
Explanation
Q.28.
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°. The value of n is given by .. [ CBSE-PMT 1995]
-
40%
a)2
-
13%
b) 1
-
33%
c)0.5
-
13%
d)0.25
Q.29.
If a diamagnetic substance is brought near north or south pole of a bar magnet, it is ... [ CBSE-PMT 1999]
-
6%
a) attracted by the poles
-
88%
b) repelled by the poles
-
0%
c)repelled by north pole and attracted by the south pole
-
6%
d)attracted by the north pole and repelled by the south pole
Q.30.
A bar magnet, of magnetic moment M , is placed in magnetic field of induction B. The torque exerted on it is ... [ CBSE-PMT 1999]
-
17%
a) M ⋅ B
-
6%
b) -M ⋅ B
-
78%
c)M × B
-
0%
d)B × M