A Level Physics Practice Exam

How can a graph of resistance versus temperature be useful in experiments with thermistors?

1. It shows a fixed resistance value

2. It helps verify the linearity of resistance

3. It illustrates the relationship between temperature and resistance

4. It determines the minimum temperature achievable

The correct answer is: It illustrates the relationship between temperature and resistance

A graph of resistance versus temperature is useful in experiments with thermistors because it illustrates the relationship between temperature and resistance. Thermistors are temperature-sensitive resistors, and their resistance varies significantly with changes in temperature. This characteristic is leveraged in various applications, such as temperature measurement and control. By plotting resistance on the vertical axis and temperature on the horizontal axis, one can observe how resistance decreases or increases with temperature. For most thermistors, specifically negative temperature coefficient (NTC) thermistors, resistance decreases as temperature increases, resulting in a distinct curve on the graph. This curve provides valuable information for understanding thermistor behavior and enables the calibration of thermistors for specific temperature ranges, enhancing their effectiveness in practical applications. Other options focus on aspects that do not capture the fundamental utility of such a graph for thermistors. Fixed resistance values are not representative of the variable nature of thermistors; verifying linearity may not apply since the relationship is typically non-linear; and determining the minimum temperature achievable is not directly inferred solely from a resistance versus temperature graph. Instead, the graph’s primary role is to visually convey the temperature-resistance relationship critical for using thermistors effectively.