Magnetism and M...

A circular coil of $$100$$ turns has an effective radius of $$0.05 m$$ and carries a current of $$0.1 A$$. How much work is required to turn it in an external magnetic field of $$1.5 { Wb }/{ { m }^{ 2 } }$$ through $${ 180 }^{ o }$$ about its axis perpendicular to the magnetic field? The plane of the coil is initially perpendicular to the magnetic field :

Which of the following is represented by the area enclosed by a hysteresis loop (B-H curve) ?

Curie temperature is defined as the temperature above which.

The magnetic lines of force inside a bar magnet.

A ferromagnetic material heated above its curie temperature. Which one is a correct statement?

The areas under the I-H hysteresis loop and B-H hysteresis loop are denoted by $$A_1$$ and $$A_2$$, then the ratio of $$\frac{A_2}{A_2}$$ is given by 

Horizontal component of the earth's field is $$3 \times 10^{-5} \, T$$  and of dip is $$53^o$$. Magnetic field of the earth at that place is

Choose the correct statement.

The earth's magnetic field at some place on magnetic equator of the earth is $$0.5\times { 10 }^{ -4 }T$$. Consider the radius of the earth at that place as $$6400 km$$. Then, magnetic dipole moment of the earth is ___________ $${ Am }^{ 2 }$$. $$\left( { \mu  }_{ 0 }=4\pi \times { 10 }^{ -7 }Tm{ A }^{ -1 } \right) $$

Which of these devices uses a magnet or electromagnet to make it work?