When a conductor is heated, its resistance ___.

• A. Increases
• B. Decreases
• C. Becomes zero
• D. Remains unchanged

Answer: (A)

When a conductor is heated, its resistance increases due to the properties of the material that makes up the conductor. As temperature rises, the atoms within the conductor vibrate more vigorously. This increased atomic activity makes it more difficult for the free electrons, which are responsible for carrying electric current, to move through the conductor. The collisions between the electrons and the vibrating atoms create additional resistance to the flow of current.

In metallic conductors, this temperature-dependent behavior is a standard characteristic. As a result, when conducting materials such as copper or aluminum are subjected to higher temperatures, their resistance consistently rises. This principle is important in electrical engineering and various applications, as it affects how circuits behave under different thermal conditions and can influence the design and materials used in electrical systems.