Energy is the strength needed to perform work, while the rate at which work is performed is called power. The unit of measurement in energy is termed as joules, whereas, a watt is the measurement unit of power.
A fine line of difference exists in the way we use the word ‘work’, in our routine activities and in science. As in our day to day life, work entails the physical and mental strain, such as dancing, singing, cooking, bathing washing, learning, etc. However, in science work implies the outcome of force acted upon an object, to cause or stop-motion, which is measured in terms of joules.
Energy and power are the two fundamental concepts related to work, which is used as the synonym, but they are not one and the same thing. So, come let’s discuss the difference between them.
Content: Energy Vs Power
Comparison Chart
| Basis for Comparison | Energy | Power |
|---|---|---|
| Meaning | Energy is described as the object's ability to perform work. | Power alludes to the rate at which work is performed upon an object. |
| Represents | How much work a person can do? | How quickly work can be done? |
| SI unit | Joules | Watt |
| Denoted by | W | P |
| Conversion | It can be converted from one form to another. | It cannot be converted from one form to another. |
| Storage | It can be stored. | It cannot be stored. |
Definition of Energy
The term ‘energy’ refers to the ability of someone or something to do work. It indicates a person’s endurance of performing work, i.e. how long, one can do a certain activity. Hence, energy is associated with a time component.
In finer terms, if an object is capable of doing work, he is said to have energy. Further, it can be transferred from one object to another, such that the object which does work, loses energy and the object on which work is done gains it. The law of conservation of energy states that energy neither produced nor destroyed, but it only changes its form. The various forms of energy are:
- Kinetic energy
- Potential energy
- Heat energy
- Light energy
- Electric energy
- Nuclear energy
- Mechanical energy
There are two sources of energy, which are renewable sources (one that can be replenished) and non-renewable sources (one that cannot be replenished). The SI unit of energy is joules, i.e. watt-hour. Thermometer, calorimeter, bolometer, etc. are several instruments which are used to measure energy.
Definition of Power
In science, power is a measure, which determines the speed of performing work, i.e. how quick or slow work is performed by an object. It is the rate at which the object performs an activity. It is the quantity of energy consumption per unit of time, i.e. if an object can transfer more energy in less time, that means the object possess greater power. In other words, it is nothing but the net force applied to an object with a specific average velocity.
Power is a quantity associated with time. Suppose, in a cycle race of 100 meters, A, B and C started riding a bicycle, in which A completed the race in 2 min, B in 1 min 40 sec and C in 3 min. The work done is same by all the three, but the difference is in their power applied by them.
The standard unit of power is Watt, expressed by symbol W and equals to Joules per second. The power delivered by a machine is measured in horsepower (hp), one hp = 746 W.
Key Differences Between Energy and Power
The points provided below explain the difference between energy and power:
- Energy can be defined as the capacity of the object to perform work. On the other hand, power implies the rate at which work is done upon an object.
- Energy indicates how much work a person can do? whereas power represents how quickly work can be done?
- Energy can be measured in terms of Joules, which is equal to watt-seconds. As against this, power is expressed in terms of Watt, which equals Joules per second.
- Energy is indicated by W, while power is indicated by P.
- Energy is neither generated nor destroyed; it is only turned from one form to another. On the contrary, power cannot be transformed from one form to another.
- Conservation of energy is possible. However, power cannot be stored.
Conclusion
So, with the above explanation, you might be clear on the differences between the two quantities. While energy is the amount of work done by force, power is the rate of energy transmission from one object to another.
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