Final answer:
The statement that heating does not affect the magnetic properties of paramagnetic and ferromagnetic substances is false. The Curie temperature demonstrates how heating can cause ferromagnetic materials to lose their magnetization and become paramagnetic, while paramagnetic materials can increase in magnetic susceptibility.
Step-by-step explanation:
The assertion that the properties of paramagnetic and ferromagnetic substances are not affected by heating is incorrect. In fact, heating can significantly impact the magnetic properties of these materials. When ferromagnetic materials are heated to a certain temperature known as the Curie temperature, they lose their magnetic properties and become paramagnetic. This is because the increased thermal energy disrupts the alignment of the magnetic domains within the material. Similarly, heating paramagnetic materials can increase their magnetic susceptibility since thermal energy may align more magnetic dipoles with the field.
Furthermore, heat and work can change the internal energy of a substance, affecting its magnetic properties. The magnetic domains in ferromagnetic materials, which are responsible for their strong magnetic effects, can become disoriented when subjected to high temperatures, causing a loss of overall magnetization.
Based on the information provided, we can conclude that the properties of paramagnetic and ferromagnetic substances can indeed be affected by heating, typically resulting in a decrease or complete loss of magnetization. Therefore, the correct answer is 'D. both Assertion & Reason are false'.