A Level Physics Practice Exam

How does temperature affect the behavior of a light bulb compared to a metal wire?

1. The resistance of the metal wire decreases with temperature

2. The resistance of the light bulb increases with temperature

3. Both components exhibit reduced conductivity at higher temperatures

4. The light bulb's resistance remains unchanged with temperature

The correct answer is: The resistance of the light bulb increases with temperature

The correct answer highlights that the resistance of the light bulb increases with temperature. This is because, in a light bulb, typically an incandescent bulb, the filament is made of a material like tungsten. As the tungsten filament heats up due to electrical current passing through it, it emits light; however, its resistance increases as its temperature rises. This is a characteristic behavior of metals at elevated temperatures—the increase in kinetic energy leads to more collisions between the conducting electrons and the atoms of the material, thus increasing resistance. In contrast, when considering a standard metal wire, as temperature rises, the resistance typically increases as well. However, some components can exhibit different behavior; not all wires behave the same way under varying temperature conditions. Overall, the behavior of the light bulb contrasting with that of the metal wire provides insight into how certain properties, such as temperature and resistance, interact in different materials. The key takeaway here is the understanding that the light bulb's resistance is dependent on its temperature, leading to increased resistance as it heats up during operation.