The Sun is the primary source of thermal energy for all living organisms. Thermal energy is the cause and temperature is the effect. All living organisms need a particular temperature for their survival. This chapter explains temperature, thermal energy (heat), how heat is transferred, the expansion of substances on heating, the fundamental laws of gases, real and ideal gases, and the ideal gas equation.
1. Temperature
- Temperature is defined as the degree of hotness of a body. A hotter body has a higher temperature than a colder body.
- It is also the property which determines whether a body is in equilibrium or not with the surroundings.
- Temperature is the property which determines the direction of flow of heat.
- It is a scalar quantity.
- SI unit: kelvin (K). Other commonly used units: degree celsius (°C) and degree fahrenheit (°F).