# Heat Index Formula

## Heat Index Formula

In shaded areas, the heat index is a measurement that combines air temperature and relative humidity. Sweating or perspiration typically lowers a person’s body temperature. The evaporation of that sweat is how heat is expelled from the body. High relative humidity, however, slows down evaporation. When the temperature is 32 °C and the relative humidity is 70%, the heat index number equals the actual air temperature. The Heat Index Formula is used to measure the heat index. Numerical problems regarding Heat Index Formula will help students understand the heat index concept in detail. Students need to learn the derivation of the Heat Index Formula. If students are unable to understand the Heat Index Formula derivation, they can take help from the Extramarks learning platform.

### What is the Heat Index?

A thermodynamic value related to air temperature and humidity is the heat index. The locations used for this measurement simulate the sensations or perceptions that a human body can experience. Because it is the sensation that the body can feel rather than the actual weather or environment temperature, it is also known as the felt air temperature. The heat index is based on temperatures in the shade, but because people frequently move across sunny areas, the heat index can provide a much lower temperature than the actual conditions of typical outdoor activities. Also, if people are exercising at the time, the heat index may give a lower temperature than the original conditions.

### Heat Index Formula:

Perspiration, or sweating, is how the human body normally cools itself. Sweating evaporates, removing heat from the body. However, high relative humidity slows evaporation. As a result, the rate of heat removal from the body slows, giving the sensation of being overheated. This effect is subjective, with different people perceiving heat differently for a variety of reasons; its measurement is based on subjective descriptions of how hot subjects feel at a given temperature and humidity. This produces a heat index, which compares one temperature and humidity combination to another. People frequently move through sunny areas, so the heat index, which is based on temperatures in the shade, can give a reading that is much lower than the actual temperature for most outdoor activities. Additionally, the heat index may give a lower temperature than the actual conditions for people who are exercising or otherwise active at the time.

### Uses of Heat Index

It is used to approximate the human body’s perception of humidity and heat in order to develop healthy or public plans that can protect human and animal safety. The heat index in this environment may be higher or lower in areas exposed to sunlight. Furthermore, people engaged in different activities may perceive different levels of heat and may not feel the heat index calculated for that day or location. Only two factors—shade temperature and atmospheric moisture (humidity)—are considered by both the heat index and the humidex, which yields a sparse estimate of thermal comfort. The perception of temperature is also influenced by other elements, such as wind, sunlight, and personal clothing preferences; these elements are parameterized in the heat index formula as constants.

### Solved Examples for Heat Index Formula

The Extramarks learning platform can help students who need help practising sample problems involving the Heat Index Formula. Using the NCERT solutions offered by Extramarks, students  can easily practice all the challenging questions pertaining to the Heat Index Formula. The notes provided by Extramarks can be used to successfully answer any question regarding the concerned topic. Students must review all the topics listed on the syllabus. The Heat Index Formula is to be applied correctly in order to solve questions. Regular revision of the Heat Index Formula is also essential. The heat index is calculated using the Heat Index Formula