A Level Physics Practice Exam

What is the effect of temperature on the resistance of ohmic conductors according to Ohm's law?

1. The resistance increases at higher temperatures

2. The resistance is unaffected by temperature

3. The resistance decreases at higher temperatures

4. Resistance behaves unpredictably with temperature

The correct answer is: The resistance increases at higher temperatures

In the context of Ohm's law and the behavior of ohmic conductors, the correct interpretation is that resistance increases at higher temperatures. This phenomenon occurs because as the temperature of a conductor rises, the atoms within the material vibrate more vigorously. This increased thermal energy leads to more frequent collisions between the charge carriers (typically electrons) and the vibrating atoms of the conductor, which in turn hinders the flow of electricity. For ohmic conductors, which obey Ohm's law (where the current passing through the conductor is directly proportional to the voltage across it), this increase in resistance is a predictable behavior at higher temperatures. Additionally, it is important to recognize that while some materials, such as semiconductors and superconductors, may exhibit different behavior regarding temperature and resistance, ohmic conductors consistently demonstrate increased resistance with rising temperature. This understanding aligns with the established principles of thermodynamics and solid-state physics, emphasizing the predictability of resistance in ohmic conductors under varying thermal conditions.