CORRECT OPTION IS iii) high retentivity and low coercivity
The capacity of a substance to remain magnetised after the external magnetising field has vanished is known as retentivity. A material with a high retentivity (for example, iron) will retain some magnetic properties and become a permanent magnet, whereas a material with a low or no retentivity will lose its magnetization.
The intensity of the applied magnetic field necessary to lower the magnetization of a ferromagnetic material to zero after the magnetization of the sample has been driven to saturation is known as coercivity.
The oersted or ampere/meter units are commonly used to measure coercivity. When a ferromagnet’s coercive field is substantial, the material is referred to as a hard or permanent magnet. Electric motors, magnetic recording medium (such as hard drives, floppy discs, or magnetic tape), and magnetic separation all use permanent magnets.
For making an electro-magnet, substance should be of
i) high retentivity and high coercivity
ii) low retentivity and high cocrcivity
iii) high retentivity and low coercivity
iv) low retentivity and low coercivity
i) high retentivity and high coercivity
ii) low retentivity and high cocrcivity
iii) high retentivity and low coercivity
iv) low retentivity and low coercivity
For making an electro-magnet, substance should be of
i) high retentivity and high coercivity
ii) low retentivity and high cocrcivity
iii) high retentivity and low coercivity
iv) low retentivity and low coercivity
i) high retentivity and high coercivity
ii) low retentivity and high cocrcivity
iii) high retentivity and low coercivity
iv) low retentivity and low coercivity
.
)
west of the geographic north. The north tip of the magnetic needle of a dip circle placed in the plane of magnetic meridian points above the horizontal. The horizontal component of the earth’s field is measured to be 
Specify the direction and magnitude of the earth’s field at the location.At a certain location in Africa, a compass points 
and 
carrying currents of 
and 
in the same direction are separated by a distance of 
. Estimate the force on a 
section of wire A.
wire carrying a current of 
is placed inside a solenoid perpendicular to its axis. The magnetic field inside the solenoid is given to be 
. What is the magnetic force on the wire?
and making an angle of 
with the direction of a uniform magnetic field of 
. What is the magnitude of the field 
at a point 
from the wire?
-turns carrying current 
.
is at distance 
from the wire. Find the force acting on the electron if its velocity is directed towards the wire.