Q.1
In the un magnetized state, magnetic domains of a magnetic substance are oriented at
  • a) 60°
  • b) 90°
  • c)Randomly
  • d)zero
Q.2
The time period of freely suspended magnet does not depend upon
  • a) length of magnet
  • b) pole strength of magnet
  • c) horizontal component of earth's field
  • d) length of the suspension
Q.3
The magnetic induction B and the force F on a pole m are related by
  • a)B=mF
  • b) F=B/m
  • c)F=Bm
  • d)none of these
Q.4
Calculate force exerted on a point N pole of 3200 A-m placed 10cm away from a point south pole of 30 A-m in air
  • a) 1 N
  • b) 1.28 N
  • c)2 N
  • d)3 N
Q.5
Magnetic potential at a point distance d from a magnetic pole of strength m is
  • a)
    ch-17_qn-232choice_img_no1.png
  • b)
    ch-17_qn-232choice_img_no2.png
  • c)
    ch-17_qn-232choice_img_no3.png
  • d) None of these
Q.6
S.I. unit of magnetic permeability is
  • a)A-m
  • b) Am2
  • c)H-m
  • d)H/m
Q.7
Force between two magnetic poles depends on
  • a) pole strength only
  • b) distance only
  • c)medium only
  • d)all the three above
Q.8
A bar magnet of magnetic moment M is placed in magnetic field of induction B. The torque exerted on it is [ GUJCET 2007]
  • a) - B . M
  • b)M × B
  • c)- M × B
  • d)M . B
Q.9
The period of oscillation of a magnet is a vibration magnetometer is 2 seconds. the period of oscillation of magnet of moment of inertia four times that of first magnet is
  • a)1 sec
  • b) 4 sec
  • c)8 sec
  • d)0.5 scc
Q.10
A point at which two or more magnetic fields cancel each other is called
  • a) focal point
  • b) inverse point
  • c)neutral point
  • d)none of the above
Q.11
The periods of oscillation of two magnets in the same field in the ratio 2:If their moment of inertia are equal, ratio of their magnetic moments is
  • a) 1 : 2
  • b) 1 : 4
  • c)2 : 1
  • d)4 : 1
Q.12
When a magnet marked N - s is suspended in a horizontal position, so that it is free to rotate, the pole marked N shall point towards
  • a) south pole of earth's magnet
  • b) north pole of earth's magnet
  • c) geographic N pole
  • d) geographic S pole
Q.13
The relative permeability of iron is of the order of ...
  • a)1
  • b) 104
  • c)zero
  • d)10-4
Q.14
Curie's law state that
  • a) magnetic susceptibility is inversely proportional to the absolute temperature
  • b) magnetic susceptibility is inversely proportional the square root of the absolute temperature
  • c)magnetic susceptibility is directly proportional to the absolute temperature
  • d)magnetic susceptibility is independent of temperature
Q.15
The permanent magnetic moment of atoms or molecules of a diamagnetic material is
  • a) small
  • b) large
  • c)negative
  • d)zero
Q.16
The relation between magnetic susceptibility χm and relative permeability µr, is
  • a) χm=µr
  • b) χm - 1=µr
  • c) χm + 1=µr
  • d) χm=1- µr
Q.17
If M is magnetic moment developed in the material having volume V, then intensity of magnetization is given by the expression
  • a)MV
  • b) M / V
  • c)M √V
  • d)M / √V
Q.18
The relation between B, H and I in S.I. unit is
  • a) B=µo ( H + I)
  • b) B=H + 4π I
  • c)H=µo ( B + I)
  • d)none of these
Q.19
A temparary magnet is made of
  • a) cast iron
  • b) steel
  • c)soft iron
  • d)stainless steel
Q.20
Water is..
  • a) diamagnetic
  • b) paramagnetic
  • c) ferromagnetic
  • d) none of these
Q.21
The relative permeability of a medium is 0.What is its magnetic susceptibility?
  • a)0.925
  • b) -0.925
  • c)1.075
  • d)-1.075
Q.22
The moment of magnet ( 15cm ×2cm × 1cm) is 1.2 A-mWhat is its intensity of magnetization ?
  • a) 4 × 104 A/m
  • b) 2 × 104 A/m
  • c)104 A/m
  • d)none
Q.23
As magnetizing field on a ferromagnetic material is increased, its permeability..
  • a) increases
  • b) decreases
  • c)remains constant
  • d)can not say
Q.24
Magnetic field do not interact with
  • a) stationary charge
  • b) moving electric charges
  • c) stationary permanent magnet
  • d) moving permanent magnets
Q.25
Two identical thin bar magnets each of length l and pole strength m are placed at right angles to each other, with north pole of one touching south pole of the other , then the magnetic moment of the system is
  • a)ml
  • b) 2ml
  • c)√2 ml
  • d)ml/2
Q.26
The ratio of magnetic potentials due to magnetic dipole in the end position to that in broad side on position for the same distance from it is
  • a) zero
  • b) ∞
  • c)1
  • d)2
Q.27
A thin bar magnet of length 2l and breadth 2b pole strength p and magnetic moment M is divided into four equal parts with length and breadth of each part being half of original magnet. Then the pole strength of each part is
  • a) p
  • b) p/2
  • c)p/4
  • d)2p
Q.28
In above question, magnetic moment of each part is
  • a) M/4
  • b) M
  • c) M/2
  • d) 2M
Q.29
A circular loop is replaced by an equivalent magnetic dipole. then the equivalent magnetic dipole has a constant
  • a)pole strength m of each pole
  • b) length 2l of dipole
  • c)product of m and 2l
  • d)all of the above
Q.30
In a bar magnet, the magnetic field lines...
  • a) are not present
  • b) depend upon the cross-section area of the magnet
  • c)go from N-pole to s pole
  • d)go from S-pole to N-pole
0 h : 0 m : 1 s