Physics 2006 JAMB Past Questions - Question 44: What is likely to happen if the glass of a thermometer v/pands more upon heating than the liquid inside?

Correct Answer

B

Explanation

If the glass of a thermometer expands more upon heating than the liquid inside, it can lead to inaccurate temperature measurements. Thermometers rely on the principle that substances, such as mercury or alcohol, expand or contract with changes in temperature. The expansion of the liquid inside the thermometer is used to indicate changes in temperature.

When the glass of the thermometer expands significantly more than the liquid, it can cause the following issues:

1. Inaccurate temperature readings: Since the glass expands more, it can push down on the liquid, compressing it and causing the thermometer to read a lower temperature than the actual temperature. This is known as a negative coefficient of expansion for the thermometer material, and it results in an underestimation of temperature.

2. Limited temperature range: Thermometers with a glass material that expands too much upon heating may have a limited range of accurate temperature measurement. They may not be able to accurately measure higher temperatures due to the expansion of the glass interfering with the liquid's expansion.

3. Reduced sensitivity: The thermometer may become less sensitive to temperature changes, making it harder to detect small temperature variations accurately.

To ensure the accuracy of temperature measurements, it is important for the glass material of the thermometer to have a coefficient of expansion that is reasonably close to the coefficient of expansion of the liquid inside. This way, the expansion or contraction of the liquid can be reliably used to indicate changes in temperature. If a thermometer exhibits such discrepancies, it may need to be recalibrated or replaced with a more suitable thermometer.