Variation of Magnetic Field
1. What is magnetization?
- The electric field produced by a moving charge
- The magnetic field generated by an external source
- The force acting on a magnetic dipole
- Magnetization is the magnetic moment produced per unit volume of a substance placed in a magnetizing field.
2. What is magnetic intensity or magnetic field strength (H)?
- The measure of the magnetic dipole moment
- It is the strength of the external magnetic field used to magnetize a substance.
- The field produced inside the material
- The total magnetic flux in a loop
3. What is magnetic susceptibility (χ)?
- It is the ratio of intensity of magnetization (I) to the magnetic field strength (H).
- The product of I and H
- The difference between B and H
- The ratio of B to H
4. What is magnetic permeability (μ)?
- It is the constant of proportionality between magnetic field (B) and magnetic field strength (H).
- The ratio of magnetic flux to electric field
- The charge stored per unit magnetic field
- The resistance to magnetic force
5. Which substances are slightly magnetized in a direction opposite to the magnetic field?
- Electromagnetic substances
- Ferromagnetic substances
- Paramagnetic substances
- Diamagnetic substances
6. Which substances are slightly magnetized along the direction of the magnetic field?
- Paramagnetic substances
- Diamagnetic substances
- Ferromagnetic substances
- Superconducting materials
7. Which substances are highly magnetized along the direction of the magnetic field?
- Ferromagnetic substances
- Paramagnetic substances
- Diamagnetic substances
- Insulators
8. What is demagnetization?
- The loss of magnetization due to disturbance in the alignment of domains in a ferromagnetic material.
- The gain of magnetization through exposure to a magnetic field
- The destruction of magnetic poles
- The neutralization of electric charge
9. How can demagnetization occur?
- By submerging it in water
- By placing it in a vacuum
- By connecting it to a battery
- By heating or applying an alternating external field.
10. What is the geographic meridian?
- A line perpendicular to the magnetic field
- A vertical plane passing through the line joining the geographical north and south poles.
- The shortest distance between two longitudes
- A horizontal plane at the equator
11. What is the magnetic meridian?
- A plane perpendicular to the equator
- The line connecting magnetic north and south underground
- A horizontal line at the poles
- A vertical plane in the direction of the earth’s magnetic field.
12. What is the angle of declination?
- The angle of the earth's tilt
- The angle between true north and east
- The angle between the magnetic field and horizontal
- The acute angle between the magnetic meridian and the geographic meridian.
13. What is the angle of dip?
- The latitude of the magnetic equator
- The angle between north and south poles
- The angle between the magnetic and geographic poles
- The angle between the direction of earth’s magnetic field and the horizontal.
14. What is the horizontal component of earth’s magnetic field?
- The angle of dip
- The total magnetic flux
- The vertical field strength
- It is the component of earth’s magnetic field in the horizontal direction at a place.
15. What is a hysteresis curve?
- A graph of magnetic field vs time
- A graph between magnetization (I) and external magnetic field (H) for a ferromagnetic material.
- A graph of electric field vs current
- A graph of temperature vs resistance
16. What is coercivity?
- The electric field needed to produce magnetism
- The magnetic field required in the opposite direction to reduce the magnetization to zero.
- The magnetic strength needed to saturate the material
- The force between two magnetic poles
17. What is retentivity?
- The angle between magnetization and external field
- The loss of magnetism due to temperature
- The magnetic strength at maximum field
- The measure of remaining magnetization in a material after the external magnetic field is removed.
