Unit of Heat

Heat is a type of energy that a body possesses, often known as thermal energy of the body. Heat, like all other kinds of energy, is measured in Joules (J). It moves from one body to the next, or from one system to the next, at varying temperatures. As a result, despite their differences in conceptions, heat and temperature are inextricably linked. The Kelvin unit of measurement is used to measure temperature.

Kelvin is also the temperature unit used by the C.G.S. In addition to the SI unit of heat energy, heat is measured in C.G.S units. The C.G.S unit of heat is also widely used. Calorie is a C.G.S unit of heat (Cal). Another heat unit is the B.T.U, which stands for British Thermal Unit. It is a more conventional unit of heat that is still used in several fields in the United Kingdom and the United States of America. The letter Q is commonly used as a sign for heat. Heat capacity is another essential concept in the context of heat. Joule per Kelvin is the heat capacity unit.

Formula of Heat

Mathematically, heat can be represented as:

Q=m ×c ×∆t 

Here,

Q= Heat

m= mass of the body

 c= specific heat of the body

∆t= change in temperature of the body

Units of heat

Joules is the SI unit of heat ( J ). When mechanical work (W) is transferred to heat energy (Q), the W by Q ratio remains constant, which is symbolised by the unit joule, according to James Prescott Joule.

i.e. WQ=Joule

Dimensional formula for joules can be given as:

1 Joule=1 kgm2/s2=[M L2 T-2] 

In C.G.S. system, the unit of heat is Calorie (cal).

1 cal=4.186 Joule 

However, in British Thermal Unit (B.T.U.):

1 btu =1055.05585 J 

Relationship of Heat and Temperature

Although they are closely related, temperature and heat are not the same thing. Temperature is the term for the measurement of heat. It determines the body’s temperature, i.e. how cold or hot it is.

For Example- When we have a high fever, we use a thermometer to measure how hot our bodies are, or the temperature of our bodies.

When two bodies of different temperatures come into touch, heat flows from the higher-temperature body to the lower-temperature body, and this heat flow continues until the temperatures of the two bodies are equal. The term for this is thermal equilibrium. Thus, temperature equilibrium between two bodies can be defined as follows: two bodies are said to be in thermal equilibrium when no heat is exchanged between them when they are in contact.

The Zeroth law of thermodynamics, based on this concept of thermal equilibrium, asserts that if two bodies A and B are in thermal equilibrium and B and C are in thermal equilibrium, then A and C are likewise in thermal equilibrium.

Note- Along with length, time, mass, ampere, mole, and candela, temperature is one of the seven fundamental quantities (used to measure luminous intensity).

Heat Transfer Mechanisms

Heat transfer mechanisms are methods for transporting hot/thermal energy between items or substances. The primary premise is adhered to, which is that kinetic energy must be in balance or equal states.

Heat transfer can take place in three different ways:

1. Conduction: In terms of being able to create a numerical explanation, conduction is the simplest heat transport mechanism. It is the transmission of kinetic energy through matter from a higher temperature to a lower temperature until equilibrium is reached. It is the mechanism through which heat is transferred between atoms and molecules that are in direct contact.

2. Convection: Convection is the transport of heat through a fluid such as air or water. The material carrier is the difference between conduction and convection. The variation in density is caused by motion. Since more heated particles are less dense, 

particles with higher temperatures will gravitate to cooler locations and vice versa. The liquid will continue to move until it reaches equilibrium.

3. Radiation: Heat is transferred by radiation, or we can say heat is transferred by electromagnetic waves, in radiation. It is not necessary to use a medium, such as light. Electromagnetic radiation is emitted by all moving and charged particles. This wave will continue to travel until it contacts with or collides with another particle. This radiation will be received as kinetic energy by the particle that receives it. Even when particles are at the same temperature, they will absorb and transmit radiation, however this will go unnoticed because the material is now in equilibrium. This approach is vital for the greenhouse effect because it keeps the temperature of Earth-like radiation constant.

Thermal Expansion

Thermal Expansion is the process by which a solid material expands in volume, length, or area as a result of heating. Any material will expand in size or shape if exposed to heat. Thermal expansion is caused by an increase in particle amplitudes.

Conclusion

The term “heat” refers to something that appears to be warm or hot. HEAT is a term that refers to a material’s entire kinetic energy. Temperature is the average kinetic energy of a body or, to put it another way, the numerical measurement of the degree of hotness. Heat transfer mechanisms are methods for transporting hot/thermal energy between items or substances.

Thermodynamics is the branch of physics that deals with the transformation of heat energy into mechanical energy or work, or the transformation of work into heat energy. Thermal Expansion is the process by which a solid material expands in volume, length, or area as a result of heating.