Correct option is (B)

Paramagnetic substances exhibit specific characteristics in the presence of an external magnetic field. Understanding these characteristics will help us choose the most appropriate answer. Let's discuss each statement individually:

A. align themselves along the directions of external magnetic field.
This is true. Paramagnetic substances have unpaired electrons, and under the influence of an external magnetic field, the atomic dipoles (due to those unpaired electrons) tend to align themselves in the direction of the magnetic field.

B. attract strongly towards external magnetic field.
This statement is the cause of some confusion. Paramagnetic substances are attracted towards an external magnetic field, but the keyword here is strongly. Compared to ferromagnetic substances, the attraction is relatively weak. Given the context of the options provided, saying they are "strongly" attracted could be misleading, but it is undeniable they are attracted nevertheless.

C. has susceptibility little more than zero.
This is correct. The magnetic susceptibility of paramagnetic materials is positive, meaning they are attracted to magnetic fields, but it is small in magnitude, typically greater than zero but far less than the susceptibility of ferromagnetic materials.

D. move from a region of strong magnetic field to weak magnetic field.
This statement is incorrect for paramagnetic substances. They are attracted to magnetic fields, implying they move from a region of weaker magnetic field to a stronger magnetic field, not the other way around.

Taking these points into account, the most accurate answer would be:

Options B: A, C Only
A) They indeed align along the direction of an external magnetic field, and C) Their susceptibility is indeed a little more than zero, indicating a weak attraction to magnetic fields. Statement B can be considered incorrect not in its entirety that they are attracted, but in the use of the term "strongly," and D is certainly incorrect regarding their movement in magnetic fields.

Correct option is (A)

Statement I : The diamagnetic property depends on temperature. This statement is incorrect. Diamagnetism is an intrinsic property of materials that arises due to the presence of completely filled electron shells. It does not depend on temperature.

Statement II : The induced magnetic dipole moment in a diamagnetic sample is always opposite to the magnetizing field. This statement is true. Diamagnetic materials have a negative magnetic susceptibility, which means that they oppose the applied magnetic field. This results in the induced magnetic dipole moment being always opposite to the magnetizing field.

Correct Option is (A)

Both Statement I and Statement II are true.

Statement I: For diamagnetic substances, the magnetic susceptibility (χ) lies between -1 and 0. This is because diamagnetic substances have a negative magnetic susceptibility, which means they have a tendency to oppose the applied magnetic field.

Statement II: Diamagnetic substances, when placed in an external magnetic field, experience a force that tends to move them from stronger to weaker parts of the field. This is due to the fact that diamagnetic substances oppose the applied magnetic field and try to minimize their exposure to it.

Correct Option is (A)

Both Assertion A and Reason R are correct, and R is indeed the correct explanation of A.

Electromagnets are commonly made of soft iron because of its high permeability, which allows it to easily magnetize in response to an external magnetic field. Its low retentivity is also desirable because it allows the magnetization to be easily reversed or removed once the external field is removed. This combination of properties makes soft iron ideal for electromagnets, which require rapid and efficient changes in magnetization.

Correct Option is (C)

Electromagnet requires high permeability and low retentivity.