A sensitive magnetic instrument can be shielded very effectively from outside magnetic fields by placing it inside a box of
1. Teak wood
2. Plastic material
3. Soft iron of high permeability
4. A metal of high conductivity
The variation of the intensity of magnetisation (I) with respect to the magnetising field (H) in a diamagnetic substance is described by the graph
1. OD 2. OC
3. OB 4. OA
If Bo is magnetic flux density in vacuum produced by a magnetising force and magnetic flux density produced by the magnetisation of a material due to the same magnetising force is Bm, then the total magnetic flux density in the material is :
Which of the following is not dimensionless?
(where symbols stand for their usual meanings in magnetism)
1.
2.
3.
4.
The unit of intensity of the magnetising field is :
1.
2.
3.
4. All of these
The magnetic susceptibility of a substance is -0.0002 at room temperature. If this substance is kept in a uniform external magnetic field B, the net field inside the substance becomes B', then :
1. B'B
2. B'B
3. B' = B
4. B' = 0
A diamagnetic substance is kept in a uniform external magnetic field B. If the net magnetic field inside the substance is B', then
1. B'B
2. B' = B
3. B'B
4. Any of the above
The magnetic moment of a magnet \((10 ~cm\times 4~cm\times1~cm)\) is \(4 ~Am^2\). Its intensity of magnetisation is:
1. 103 A/m
2. 102 A/m
3. 105 A/m
4. 104 A/m
S.I. unit of intensity of magnetization is:
1. | Ampere-metre | 2. | Ampere-metre2 |
3. | Ampere/metre | 4. | Ampere/metre2 |
The magnetization of a piece of iron or steel:
1. | depends on the strength of the magnetizing field. |
2. | depends on external conditions such as temperature. |
3. | cannot be done beyond the saturation point. |
4. | all of these. |