Question

In the S.I system, the unit of temperature is:

Answer 1

In this question, we will see the basic information about temperature. This will give us the required answer. Further, we will discuss the basics of thermometer. Also, we will see different types of thermometer and understand their limits.

Complete answer:
As we know that the temperature is defined as the quantity measured by any thermometer. Also, here temperature is related to the average kinetic energy of atoms and molecules in a given system. When we know about the term absolute zero, it is the temperature at which there is no molecular motion in the given system. Further, we know that there are three main temperature scales that are: Celsius, Fahrenheit, and Kelvin.
Therefore, the S.I unit of temperature is Kelvin, which is represented by K.

Additional information:
Thermometer is a device that measures temperature or temperature gradient. A thermometer has two important elements that are:
A temperature sensor- bulb of mercury-in-glass thermometer acts as a temperature sensor; in this some changes occur with a change in temperature.
Some means of converting this change into a numerical this change into a numerical value.
A clinical thermometer is a small medical thermometer with a short but finely calibrated range. These are used by doctors in clinics. A clinical mercury thermometer has mercury in them which expands with the temperature.
The alcohol thermometer is also known as spirit thermometer. It is an alternative to the mercury-in-glass thermometer and has the same functions.
The contents of alcohol are less toxic and will evaporate quickly as compared to the mercury-in-glass thermometer. Since, alcohol starts boiling at 80℃ while the boiling point of mercury is 375℃. Therefore, a mercury thermometer is used to measure high temperatures. The temperature of boiling water is 100℃ but the maximum limit that an alcohol thermometer can measure is 80℃. So, an alcohol thermometer cannot measure the temperature of boiling water as it has the limit to measures up to 80℃.

Note:
There are different types of thermometer present for different purposes, like- clinical thermometer; laboratory thermometer etc. thermometers have different limits. The S.I unit of temperature is Kelvin (K), 1K=-273.15 degree Celsius.