Statement A: In Kelvin temperature, the symbol () is not used.
The statement A is true. In Kelvin temperature, the symbol () is not used. Kelvin is the unit of temperature in the International System of Units (SI). It is named after the Scottish physicist William Thomson, 1st Baron Kelvin. In the Kelvin scale, there are no negative temperatures, and the zero point is defined as absolute zero, the lowest possible temperature. The symbol for Kelvin is K, and it is always written without the degree symbol (°). The absence of the degree symbol differentiates Kelvin from Celsius and Fahrenheit temperature scales.

Statement B: Mercury is used in glass thermometers because it does not stick with glass.
The statement B is true. Mercury is used in glass thermometers because it does not stick with glass. Glass thermometers work based on the principle of thermal expansion. As the temperature increases, the liquid inside the thermometer expands and moves up the narrow tube, indicating the temperature reading. Mercury has several properties that make it suitable for use in glass thermometers:

1. High coefficient of thermal expansion: Mercury has a high coefficient of thermal expansion, which means it expands significantly when heated. This property allows for accurate temperature readings as small changes in temperature cause noticeable movement of the mercury column in the thermometer.

2. Wide temperature range: Mercury remains in a liquid state over a wide range of temperatures, from -38.83°C (-37.89°F) to 356.73°C (674.11°F). This allows for the measurement of both low and high temperatures accurately.

3. Low freezing point: Mercury has a very low freezing point of -38.83°C (-37.89°F), which allows it to remain in a liquid state at typical room temperatures. This ensures that the thermometer does not freeze and become unusable in normal conditions.

4. Non-adhesive properties: Mercury does not stick to the glass surface of the thermometer. This property allows for smooth movement of the mercury column within the narrow tube, ensuring accurate temperature readings.

5. Visible and reflective: Mercury is a dense liquid that exhibits a shiny, reflective surface. This makes it easy to observe and read the temperature markings on the glass thermometer.

Due to these properties, mercury has been traditionally used in glass thermometers for various applications, including laboratory measurements, industrial processes, and everyday household use. However, due to environmental concerns regarding the toxicity of mercury, alternative digital thermometers or alcohol-filled thermometers are now commonly used instead.