The variation of magnetic susceptibility with the temperature of a ferromagnetic material can be ploted as

The $B-H$ curve for a ferromagnet is shown in the figure. The ferromagnet is placed inside a long solenoid with $1000 \mathrm{turns} {\mathrm{cm}}^{-1}$. The current that should be passed in the solenoid to demagnetize the ferromagnet completely is, 

Magnetic materials used for making permanent magnets $\left(\mathrm{P}\right)$ and magnets in a transformer $\left(\mathrm{T}\right)$ have different properties of the following, which property best matches for the type of magnet required?

A perfectly diamagnetic sphere has a small spherical cavity at its centre, which is filled with a paramagnetic substance. The whole system is placed in a uniform magnetic field $\overrightarrow{\mathrm{B}}$. Then the field inside the paramagnetic substance is:

Consider the regular array of vertical identical current-carrying wires (with the direction of current flow as indicated in the figure below) protruding through a horizontal table. If we scatter some diamagnetic particles on the table, they are likely to accumulate-