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

Abhishek and Deepak have two samples of magnetic materials X and Y. Experimentally they determine the following properties of the samples.
| | Retentivity | Coercivity |
| :--- | :--- | :--- |
| X | 1.5 T | 20 Am?¹ |
| Y | 1.0 T | 100 Am?¹ |
Considering this, choose best choice

Which of the following statements are correct?
(A) Electric monopoles do not exist whereas magnetic monopoles exist.
(B) Magnetic field lines due to a solenoid at its ends and outside can not be completely straight and confined.
(C) Magnetic field lines are completely confined within a toroid.
(D) Magnetic field lines inside bar magnet are not parallel.
(E) χ = -1 is the condition for a perfect diamagnetic material, where χ is its magnetic susceptibility.

Choose the correct answer from the options given below:

An iron rod of volume ${10}^{-3}{\mathrm{m}}^3$ ${}^{}{}^{}$ and relative permeability 1000 is placed as core in a solenoid with 10 turns/cm. If a current of $0.5\mathrm{A}$ $$ is passed through the solenoid, then the magnetic moment of the rod will be:

If the distance between successive compressions and rarefaction in a sound wave is 2 m and velocity of sound is 360 m/s, then the frequency is

The relative permeability of iron is 5500. What is its magnetic susceptibility?