Temperature is a physical quantity that measures hotness or coldness of the body. The body that feels hot has a higher temperature than the body that feels cold. The device used to measure temperature is called thermometer.
We have experienced that a glass of ice cold water placed on a table (at room temperature) on a hot summer day eventually becomes warm; but a cup of hot coffee placed on the table cools down. So, an exchange of energy has taken between-water or coffee and the surrounding. This transfer of energy takes place till thermal equilibrium is reached.
So, temperature is that physical quantity of an object which tells whether an object is in thermal equilibrium with the other object or not. If the two objects kept in contact are not in thermal equilibrium, then heat will flow from object at high temperature to the object at lower temperature. When the temperature of both the objects becomes equal the heat flow stops. So, temperature is that physical quantity of an object which decides the direction pf flow of heat.
The S.I. unit of temperature is Kelvin and its value is \(\frac { 1 }{ 273.16 } \) point of water. Temperature is a scalar 273.16 quantity.
Other than kelvin scale, temperature can be measured in degree Celsius, fahrenheit, etc.
Heat : Heat is a form of energy. The hotness or coldness of any object is felt by it. When a hot object and a cold object are brought in contact with each other then the energy flows from hot to cold object. The energy transferred in this process is heat. The unit of heat is joule (J) or calorie. One calorie is defined as the quantity of heat energy required to raise the temperature of one gram (lg) of water from 14.5°C to 15.5°C.
- 1 Kcal = 103 Calorie
- 1 calorie = 4.186 Joule.
