When an iron bar is heated from 10 degrees Celsius to 100 degrees Celsius, several changes occur. Here's an overview of what happens:
Thermal Expansion: As the iron bar is heated, it undergoes thermal expansion. Iron expands when heated and contracts when cooled. The length, volume, and dimensions of the bar will increase as it absorbs heat and its temperature rises.
Increased Kinetic Energy: Heating the iron bar increases the kinetic energy of its atoms and molecules. This increase in kinetic energy causes the atoms to vibrate more vigorously. As a result, the average distance between atoms increases, leading to the expansion mentioned earlier.
Change in Electrical Conductivity: Iron is a good conductor of electricity. When heated, the thermal energy causes an increase in the mobility of electrons, leading to a slight increase in electrical conductivity. However, this effect is generally small within the temperature range mentioned.
Change in Magnetic Properties: Iron is a ferromagnetic material, which means it can be magnetized. Heating the iron bar to a high temperature, such as 100 degrees Celsius, weakens its magnetic properties. At temperatures below its Curie temperature (around 770 degrees Celsius for pure iron), the iron retains its ferromagnetic properties.
No Phase Change: Heating the iron bar from 10 degrees Celsius to 100 degrees Celsius does not cause it to undergo a phase change. Iron remains in its solid state throughout this temperature range.
Overall, heating the iron bar from 10 degrees Celsius to 100 degrees Celsius primarily leads to thermal expansion and an increase in the kinetic energy of its atoms and molecules. It does not significantly alter its fundamental properties or cause a change in phase.