The magnetic moment of a short dipole is \(100\) A-m2. The magnetic induction in vacuum at \(1\) m from the dipole on the axis of the dipole is:
1. | \(2\times10^{-5}~\text{T}\) | 2. | \(10^{-5}~\text{T}\) |
3. | \(2~\mu\text{T}\) | 4. | \(1~\mu\text{T}\) |
A deflection magnetometer is placed in tanA position. The bar magnet is placed in :
1. East-West direction
2. North-south direction
3. North-east direction
4. South-West direction
Each of the two identical magnets, when suspended alone, makes 30 oscillations per minute at a place. The number of oscillations per minute, if they are fixed at right angles ( to form a cross) and allowed to oscillate in the same field will be approximate:
1. 25 oscillation/minute
2. 30 oscillation/minute
3. 60 oscillation/minute
4. 15 oscillation/minute
If the apparent value of dip at a place in two perpendicular vertical planes are respectively 30 and 45, then the true angle of dip at that place is
1. cot-1(2)
2. tan-1(2)
3. cot-1()
4. cot-1()
The magnetic moment of a magnet \((10 ~\text{cm}\times 4~\text{cm}\times1~\text{cm})\) is \(4 ~\text{Am}^2\). Its intensity of magnetisation is:
1. \(10^{3}~\text{A/m}\)
2. \(10^{2}~\text{A/m}\)
3. \(10^{5}~\text{A/m}\)
4. \(10^{4}~\text{A/m}\)
If the magnetic field of the earth at any point on the magnetic equator is 0.410-4 T, then the value of the magnetic field at the magnetic pole of the earth is approximately
1. 0.410-4 T
2. 0.210-4 T
3. 0.810-4 T
4. 0.310-4 T
S.I. unit of intensity of magnetization is:
1. | Ampere-metre | 2. | Ampere-metre2 |
3. | Ampere/metre | 4. | Ampere/metre2 |
When the plane of a dip circle is along the magnetic meridian, the period of oscillations of dip needle is T1. When the plane of dip circle is perpendicular to the magnetic meridian, the period of oscillations is T2, then T1/T2 is (Angle of dip = 30)
1.
2. 1
3. 2
4.
A ferromagnetic material is placed in an external magnetic field. The magnetic domains:
1. | must increase in size. |
2. | must decrease in size. |
3. | may increase or decrease in size. |
4. | disappear. |
Magnetic permeability is maximum for
1. Diamagnetic substance
2. Paramagnetic substance
3. Ferromagnetic substance
4. Same for all three substances