What is Energy? 

Energy is a property that is quantitative in nature and transferred within an object so that it will be able to perform the desired work. It is measured in joules. A joule is described as the energy transferred to any object to move the body up to a distance of 1 meter when the opposing force is 1 Newton.

Energy can take various forms, which include: mechanical, electrical, magnetic, gravitational, chemical, ionization, nuclear, chromo dynamic, elastic, mechanical wave, sound wave, radiant, rest, and thermal. According to the law of conservation, energy cannot be created or destroyed but can be changed from one form to another.

Types of Energy

Mechanical energy: The energy that an object has due to its position or motion. It can also be defined as the summation of all the rotational and the translational potential as well as kinetic energies. Mechanical energy can be further classified into two more types: kinetic energy and potential energy. 

Electrical energy: The energy which is formed due to the motion of electric charge. The charged particles are responsible for generating the force, which can be either attracting or repulsive in nature.  

Magnetic energy: The energy that is formed due to magnetic fields, which are generated by electric currents. Magnetic fields contain energy, which is referred to as magnetic energy. 

Gravitational energy: The type of energy that is possessed by any object due to its distance from Earth. It is associated with the gravity of the object. Gravity is a force that exerts a downward motion toward the ground. Any object that is elevated from the ground will have gravitational energy. The acceleration of a free-falling body is a constant value, which is equivalent to 9.8 m/s². Gravitational energy is similar to potential energy since the potential energy of an object is also dependent on its position.

Chemical energy: The potential of a substance in which a chemical reaction takes place that causes the substance to transform into some other form. Such energy is generally stored within the chemical components.  

Ionization energy: The potential energy of any substance which causes it to lose electrons from the atom. This is the minimum energy that is required to discharge or lose an electron.  

Nuclear energy: The potential energy which causes to nucleons to bind close to each other, therefore forming a nucleus.  

Chromodynamic energy: The energy used to bind quarks together, which leads to the formation of hadrons. 

Elastic energy: The type of energy stored in a material or system when it is subjected to deformation which is elastic in nature. This occurs when the material or the object is stretched, compressed or maybe deformed. 

Mechanical wave energy: The energy caused by the wave which is deforming in any elastic material. 

Sound energy: The energy caused in a fluid when there is an elastic compression or a displacement of the particles. The fluid is the medium of storage for both kinetic and potential energy. 

Radiant Energy: The energy caused by the flow of electromagnetic waves that can travel through space in all directions. These electromagnetic radiations are made up of photons.  

Rest energy: The energy possessed by any object when it is at rest due to the rest mass of the object. 

Thermal energy: The energy contained by any object within itself or the system due to the internal movement of particles from one place to another. This can also be referred to as kinetic energy of motion of particles. 

Energy Consumption and Conservation

Energy consumption is a fundamental study required to save, store, and supply energy for all of us and for future generations. Energy consumption can be measured by measuring how much energy is produced and how much energy is needed by consumers. When the energy supplied equals the energy demanded, there is an equal distribution. Conservation of energy is important, and that is the reason this generation depends more on renewable sources of energy than non-renewable sources of energy.   

What is Power? 

Power is the total amount of energy that has been transferred or converted into work per unit of time. In other words, power is the rate with which work has been done in correspondence to time. Its unit is watts (W). A watt is equal to one joule per second and is a scalar quantity.

For example, in the case of a motor, power is described as the product of its torque and angular velocity. In the case of a ground vehicle, the total power required to move the vehicle is defined by multiplying the force of traction on the wheels by the velocity of the vehicle. The power of a jet-propelled vehicle is calculated by the product of the thrust and its velocity. The relationship of power and energy is that energy is the ability or the capacity of a body to cause a change, while power is the rate of energy used.  

Types of Power

Average power: The average amount of work completed or done within a unit of time. For example, while burning a kilogram of coal, it releases much more energy then a kilogram of TNT. However, the power generated by the TNT is much higher, and its reaction is way too fast, leading to the release of energy much faster than in the case of coal. 

The formula for average power can be given as: 

P_avg= ΔW/ΔT 

Where ΔW denotes the amount of work done and ΔT is the duration of time. 

Mechanical power: In case of mechanical systems, power is described as the combination of both the forces and the movement. In general, it is calculated by the product of force on the object to the velocity of the object. For a motor, power is given by multiplying the torque on a shaft with the angular velocity of the shaft. 

Electrical power: The rate at which electrical energy is transferred to the system by an electric circuit. This is generally produced with the help of generators.  

Radiant power: The power that is emitted from any source of light within a single second. Mathematically, it can be written as:  

                                             P= I (4πr²) 

Context and Applications 

This topic is significant in professional exams for both undergraduate and graduate courses, especially for:       

• Bachelors in Science (Physics) 
• Masters in Science (Physics)