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 0.26G and the dip angle is 60°. The magnetic field of the earth at this location is:

1. 0.25 G

2. 0.20 G

3. 0.35 G

4. 0.52 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 2A. If the number of turns is 1000 per metre, the magnetic field intensity H is:

$$\begin{gathered} 1. 2\times {10}^2 A/m \\ 2. 2\times {10}^3 A/m \\ 3. 2 A/m \\ 4. 20 A/m \end{gathered}$$

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 2A. If the number of turns is 1000 per metre, the magnetising field B is:

1. 10 T

2. 1 T

3. 0.1 T

4. 2 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 2A. If the number of turns is 1000 per metre, the magnetization, M is:

$$\begin{gathered} 1. 8\times {10}^5 A/m \\ 2. 6\times {10}^5 A/m \\ 3. 6.5\times {10}^5 A/m \\ 4 8.9\times {10}^5 A/m \end{gathered}$$

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 2A. If the number of turns is 1000 per metre, the magnetizing current $I_m \mathrm{is}:$

1. 746 A

2. 700 A

3. 729 A

4. 794 A

A domain in ferromagnetic iron is in the form of a cube of side length 1µm. 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 9.27×10^–24 A $m^2]$ 

^{$$\begin{gathered} 1. 8.0\times {10}^{-13} A m^2 \\ 2. 8.0\times {10}^{-12} A m^2 \\ 3. 7.0\times {10}^{-13} A m^2 \\ 4. 7.0\times {10}^{-12} A m^2 \end{gathered}$$}

A domain in ferromagnetic iron is in the form of a cube of side length 1µm. The magnetisation of the domain 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 9.27×10^–24 A $m^2]$ 

^{$$\begin{gathered} 1. 9.0\times {10}^5 A{m}^{-1} \\ 2. 8.0\times {10}^5 A{m}^{-1} \\ 3. 11\times {10}^5 A{m}^{-1} \\ 4. 3.0\times {10}^5 A{m}^{-1} \end{gathered}$$}

Which one of the following is correct?

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

1. (g), (c)

2. (d), (f)

3. (a), (b)

4. (c), (e)