The variation of magnetic susceptibility ( ) with absolute...

For material X, the susceptibility $\chi$ is positive and varies inversely with absolute temperature ($T$) since the graph is a rectangular hyperbola. This behaviour obeys Curie's law ($\chi \propto \dfrac{1}{T}$), which is a characteristic property of paramagnetic materials.

For material Y, the susceptibility $\chi$ is negative and remains constant with temperature (a straight line parallel to the $T$-axis). This is a characteristic property of diamagnetic materials, as their susceptibility is independent of temperature.

Therefore, material X is paramagnetic and material Y is diamagnetic.

Answer: X is paramagnetic and Y is diamagnetic