Which of the following is the correct representation of magnetic field lines?

 

1. (g), (c)

2. (d), (f)

3. (a), (b)

4. (c), (e)

Which one of the following is correct?

The earth’s magnetic field at the equator is approximately 0.4 G. The earth’s dipole moment is:
(Radius of earth, \(R_{E}=6.4\times10^{6} \) m)
1. \(1.05\times10^{23}\)$\mathrm{}$ A-m²
2. \(8.0\times10^{22}\) A-m²
3. \(4.5\times10^{23}\) A-m²
4. \(2.10\times10^{23}\) A-m²

In the magnetic meridian of a certain place, the horizontal component of the earth’s magnetic field is \(0.26~\text{G}\) and the dip angle is \(60^{\circ}\). The magnetic field of the earth at this location is:
1. \(0.25~\text{G}\)
2. \(0.20~\text{G}\)
3. \(0.35~\text{G}\)
4. \(0.52~\text{G}\)

A solenoid has a core of material with relative permeability \(400.\) The windings of the solenoid are insulated from the core and carry a current of \(2\) A. If the number of turns is \(1000\) per metre, the magnetic field intensity \(H\) is:
1. \(2\times10^2\) A/m
2. \(2\times10^3\) A/m
3. \(2\) A/m
4. \(20\) A/m

A solenoid has a core of material with relative permeability \(400.\) The windings of the solenoid are insulated from the core and carry a current of \(2~\text{A}\). If the number of turns is \(1000\) per metre, the magnetising field \(B\) is:
1. \(10~\text{T}\) 
2. \(1~\text{T}\)
3. \(0.1~\text{T}\)
4. \(2~\text{T}\)

A solenoid has a core of material with relative permeability \(400\). The windings of the solenoid are insulated from the core and carry a current of \(2~\text{A}\). If the number of turns is \(1000\) per metre, the magnetization, \(M\) is:
1. \(8\times10^{5}~\text{A/m}\)
2. \(6\times10^{5}~\text{A/m}\)
3. \(6.5\times10^{5}~\text{A/m}\)
4. \(8.9\times10^{5}~\text{A/m}\)$\mathrm{}$

A domain in ferromagnetic iron is in the form of a cube of side length \(1\) µm. The maximum possible dipole moment is:
[The molecular mass of iron is \(55\) g/mole and its density is \(7.9\) g/cm³. Assume that each iron atom has a dipole moment of \(9.27\times 10^{-24}\) Am²]
1. \(8.0\times10^{-13}\) Am²
2. \(8.0\times10^{-12}\) Am²
3. \(7.0\times10^{-13}\) Am²
4. \(7.0\times10^{-12}\) Am²

Figure shows the graph for magnetic hysteresis for a ferromagnetic materail. From the graph, magnetic retentivity for the material is-

1. 2.5 T

2. 1.2 T

3. 1 T

4. 4 T

The figure shows a small magnetized needle P placed at a point O. The arrow shows the direction of its magnetic moment. The other arrows show different positions (and orientations of the magnetic moment) of another identical magnetized needle Q. Then: