Question 1 :
Assertion (A) : When small holes are made in the body of the magnet, its magnetic moment decreases <br>Reason (R) : For a magnet Intensity of magnetisation remains constant and on making holes,magnetised volume decreases, hence magnetic moment decreases
Question 3 :
Which of the following substances magnetic susceptibility$\displaystyle { X }_{ m }$ is negative?
Question 4 :
If ${\mu}_{0}$ is absolute permeability of vacuum and ${\mu}_{r}$ is relative magnetic permeability of another medium, then permeability $\mu$ of the medium is
Question 6 :
The magnetic susceptibility of a material of a rod is $499$. Permeability of vacuum $(\mu _0)$ is $4\pi \, \times\, 10^{-7}\, Hm^{-1}$. Absolute permeability of the material (in $Hm^{-1}$) of the rod is:
Question 8 :
The magnetic lines of forces due to the horizontal component of Earth's magnetic field will be
Question 9 :
A susceptibility of a certain magnetic material is 400. What is the class of the magnetic material?
Question 11 : <span class="wysiwyg-font-size-medium"><span class="wysiwyg-font-size-medium"><p class="wysiwyg-text-align-left">The area enclosed by a hysteresis loop is a measure of</p>
Question 12 : <span class="wysiwyg-font-size-medium"><span class="wysiwyg-font-size-medium"><p class="wysiwyg-text-align-left">Alnico is used for making permanent magnets because it has</p>
Question 13 :
The magnetic moment produced in a substance of 1 g is $6 \times 10^{-7}\, A-m^2$. If its density is $5 \,\,g/cm^3$, then the intensity of magnetisation in A/m will be :<br/>
Question 14 : <span class="wysiwyg-font-size-medium"><span class="wysiwyg-font-size-medium"><p class="wysiwyg-text-align-left">The geometric length of a bar magnet of pole strength 80 A.m. and magnetic moment 4 amp m$^{2}$ :<br/></p>
Question 15 :
A magnetic needle is kept in a nonuniform magnetic field. It<br>
Question 16 :
Assertion: Magnetic susceptibility is a pure number.
Reason: The value of magnetic susceptibility for vacuum is one.
Question 17 :
The ratio of intensity of magnetisation and magnetising field is called
Question 18 : <span class="wysiwyg-font-size-medium"><span class="wysiwyg-font-size-medium"><p class="wysiwyg-text-align-left">A short bar magnet produces magnetic fields of equal induction at two points on the axial line and the other on the equatorial line. Then the ratio of the distance is <br/></p>
Question 22 :
Susceptibility of a magnetic substance is found to depend on temperature and the strength of the magnetising field. The material is a         <br/>
Question 23 :
Which of these devices uses a magnet or electromagnet to make it work?
Question 24 :
A bar magnet of magnetic moment 80 units is cut into two halves of equal length, the magnetic moment of each half will be :<br>
Question 25 :
Assertion: Substances which at room temperature retain their ferromagnetic property for a long period of time are called permanent magnets.
Reason: Permanent magnet can be made by placing a ferromagnetic rod in a solenoid and passing current through it.
Question 26 :
A watch glass containing some powdered substance is placed between the pole pieces of a magnet. Deep concavity is observed at the centre. The substance in the watch glass is
Question 27 :
An example of a perfect diamagnet is a superconductor. This implies that when a superconductor is put in a magnetic field of intensity $B$, the magnetic field $B_S$ inside the superconductor will be such that :
Question 28 :
A thin diamagnetic rod is placed vertically between the poles of an electromagnet. When the current in the electromagnet is switched on, then the diamagnetic rod is pushed up, out of the horizontal magnetic field. Hence the rod gains gravitational potential energy. The work required to do this comes from.
Question 30 : <span class="wysiwyg-font-size-medium"><span class="wysiwyg-font-size-medium"><p class="wysiwyg-text-align-left">If I is the intensity of earth's magnetic field, H its  horizontal component and V the vertical component, then these are related as :<br/></p>
Question 31 :
Angle of dip at a place is $30^0 $. If the vertical component of earth's magnetic field at that point is $7.5\times 10^{-5}T$. then the total magnetic field of earth at that point will be :
Question 32 :
The relative permeability of silicon is $0.99837$ and that of palladium is $1.00692$, choose the correct option from the following :
Question 33 :
The relative permeability of a medium is $0.075$. What is the magnetic susceptibility?
Question 34 : <span class="wysiwyg-font-size-medium"><span class="wysiwyg-font-size-medium"><p class="wysiwyg-text-align-left">Alnico is used for making permanent magnets because it has</p>
Question 36 :
The ratio of intensity of magnetisation and magnetising field is called
Question 40 :
Which of the following is not true about the advantages of electromagnet over permanent magnet?
Question 41 :
The magnetic induction field strength at a distance 0.2 m on the axial line of a short barmagnet of moment 3.6 Am$^{2}$is
Question 43 :
A dip needle in a plane perpendicular to magnetic meridian will be
Question 44 :
$\chi _{1}$and $\chi _{2}$ are susceptibilities of a diamagnetic substance at temperatures $T_{1}K$ and $T_{2}K$ respectively, then,
Question 45 : <p class="wysiwyg-text-align-left">The relative permeability is represented by$\mu _{r}$ and susceptibility is denoted by $\chi $ for a magnetic substance then for a paramagnetic substance.<br/></p>
Question 46 : <p class="wysiwyg-text-align-left">Two short bar magnets of moments $512Am^{2}$ and $1000Am^{2}$ are placed on a line $18cm$ apart. The magnetic field is zero at a point Q between them. The field at Q when one magnet is reversed pole to pole is:<br/></p>
Question 47 :
The intensity of magnetization of a bar magnet is $5.0\times { 10 }^{ 4 }\ { Am }^{ -1 }$. The magnetic length and the area of cross-section of the magnet are $12\ cm$ and $1\ { cm }^{ 2 }$ respectively. The magnitude of magnetic moment of this bar magnet is (in SI unit):
Question 48 :
The magnetic induction at a distance of 20cm on the equatorial line of a short bar magnet with a magnetic moment 60 Am$^{2}$ is
Question 49 :
Read the following statements and answer whether the given statement is true or false.Lenz's law is used to find out the magnitude of the induced e.m.f.<br/>
Question 50 :
A point charge $Q (= 3 \times 10^{-12}C)$ rotates uniformly in a vertical circle of radius $R = 1\ mm$. The axis of the circle is aligned along he magnetic axis of the earth. At what value of the angular speed $\omega$, the effective magnetic field at the center of the circle will be reduced to zero? (Horizontal component of Earth's magnetic field is $30$ micro Tesla).
Question 51 :
A dip needle in a plane perpendicular to magnetic meridian will be :<br>
Question 52 :
A long straight horizontal cable carries a current of $2.5$A in the direction $10^0$ south of west to $10^0$ north of east. The magnetic meridian of the place happens to be $10^0$ west of the geographic meridian. The earth's magnetic field at the location is $0.33$G, and the angle of dip is zero. Locate the line of neutral points (ignore the thickness of the cable). (At neutral points, magnetic field due to a current carrying cable is equal and opposite to the horizontal component of earth's magnetic field.)
Question 53 :
The magnetic susceptibility of a paramagnetic substance is $3 \times 10^{-4} Am^{-1}$. The intensity of magnetisation will be : ( $H = 4 \times 10^3$ )
