Given below are two statements:Statement-I: Susceptibilities of parama...
Statement-I: Susceptibilities of paramagnetic and ferromagnetic substances increase with decrease in temperature.
The statement-I is true. The susceptibility of paramagnetic and ferromagnetic substances indeed increases with a decrease in temperature.
Explanation:
Paramagnetism:
- Paramagnetic materials are those materials that have unpaired electrons in their atoms or molecules.
- In the presence of an external magnetic field, these unpaired electrons align themselves with the field, resulting in a net magnetization of the material.
- The alignment of these magnetic moments is not perfect, and their orientations are random in the absence of a magnetic field.
- When a magnetic field is applied, the magnetic moments tend to align with the field, but due to thermal motion, they also experience randomizing effects.
- As the temperature decreases, the thermal motion of the electrons decreases, and they can align more easily with the external magnetic field.
- Therefore, the susceptibility (a measure of the material's response to an external magnetic field) of paramagnetic materials increases with a decrease in temperature.
Ferromagnetism:
- Ferromagnetic materials are those materials that have spontaneous magnetization even in the absence of an external magnetic field.
- In these materials, the magnetic moments of neighboring atoms or molecules align parallel to each other, creating magnetic domains.
- Below a certain temperature called the Curie temperature, these magnetic domains can align in a preferred direction, resulting in a strong net magnetization of the material.
- As the temperature decreases below the Curie temperature, the thermal motion of the atoms or molecules decreases, allowing for better alignment of the magnetic domains.
- This alignment leads to an increase in the susceptibility of the ferromagnetic material with decreasing temperature.
Therefore, both paramagnetic and ferromagnetic substances show an increase in susceptibility with a decrease in temperature.
Statement-II: Diamagnetism is a result of orbital motions of electrons developing magnetic moments opposite to the applied magnetic field.
The statement-II is true. Diamagnetism is indeed a result of orbital motions of electrons developing magnetic moments opposite to the applied magnetic field.
Explanation:
- Diamagnetic materials are those materials that have all their electrons paired and no net magnetic moment in the absence of an external magnetic field.
- When a magnetic field is applied, the motion of the electrons in their atomic or molecular orbitals induces a small magnetic moment in the opposite direction to the applied field.
- This induced magnetic moment opposes the applied field and causes the material to be weakly repelled by the magnetic field.
- The orbital motion of the electrons is responsible for the development of these induced magnetic moments.
- Diamagnetism is a universal property of all materials to some extent, but it is usually overshadowed by the stronger paramagnetic or ferromagnetic effects in most materials.
- In contrast to paramagnetic and ferromagnetic materials, the susceptibility of diamagnetic materials decreases with a decrease in temperature.
- This is because as the temperature decreases, the thermal motion of the electrons decreases, leading to a decreased induced magnetic moment in the opposite direction to the applied field.
Hence, Statement-II is also true.
Therefore, the correct answer is option 'A' - Both Statement-I and Statement-II are true.
Given below are two statements:Statement-I: Susceptibilities of parama...
According to curies law, magnetic susceptibility is inversely proportional to temperature for a fixed value of external magnetic field i.e. x = C/T.
The same is applicable for ferromagnet & the relation is given as
(TC is curie temperature) Diamagnetism is due to non-cooperative behaviour of orbiting electrons when exposed to external magnetic field.
To make sure you are not studying endlessly, EduRev has designed JEE study material, with Structured Courses, Videos, & Test Series. Plus get personalized analysis, doubt solving and improvement plans to achieve a great score in JEE.