The maximum and minimum temperatures of the previous day, reported in weather reports, are measured by which of the following thermometer?

Maximum - Minimum thermometer

The correct answer is option 3. Maximum - Minimum thermometer.

A Maximum-Minimum thermometer, also known as a min-max or max-min thermometer, is designed to measure and record the maximum and minimum temperatures over a specific period, typically 24 hours. It consists of a U-shaped tube filled with a special liquid, often mercury, that expands and contracts with temperature changes.

Here's how it works:

1. Maximum Temperature:  One arm of the U-tube has a constriction near the bulb end. As the temperature rises, the liquid expands, pushing the mercury column in the arm with the constriction. However, the constriction prevents the mercury from returning to the bulb when the temperature drops.

2. Minimum Temperature:  The other arm of the U-tube has a small steel index. This index is pushed ahead of the contracting mercury as the temperature drops. The lowest temperature reached is indicated by the position of the steel index.

By checking the positions of the mercury column and the steel index, one can determine the maximum and minimum temperatures recorded during a specific period.

This type of thermometer is commonly used in meteorology and weather stations to track temperature fluctuations over a day. It provides a convenient way to assess temperature variations without requiring constant monitoring.