Work and Energy


Let’s pull our focus on the state function and also the scalar quantity that everybody uses in day to day life and that is Energy. In the context of physics energy is basically the quantitative property that transfers to an object in order to perform work or to heat the object. Energy is a conserved quantity which means that energy can neither undergo creation nor destruction. Energy produces:

  • Light
  • Motion
  • Heat
  • Sound
  • Growth
  • Technology


Discovery of Energy and its Uses

Between 1842 and 1847, Julius Robert von Mayer, James Prescott Joule and Hermann Ludwig Ferdinand Von Helmohotz came across to the credit of discovery and publishing of the Law of conservation of Energy.

All matter and psychological processes for example- thinking, attitude, beliefs and every emotion consists of energy which is superimposable on each other which we know by the name of Human Energy.

We divide the use of Energy among four economic sectors:

1. Residential sector- We make use of energy for domestic purpose e.g. Cooking food, heating water, other electrical appliances and for sure the domestic work includes mechanical and muscular energy.

2. Commercial sector- Use of energy in the commercial sector includes heating, cooling and lighting of commercial buildings and machines such as fax, printer, copier and computer.

3. Transport sector- This sector own hundred per cent dependence on energy. Nearly seventy per cent of petroleum and other fuels like diesel go into the transport sector. Without fuel, transport section has no importance but the transport sector gives a lot of contribution to air pollution through the pollutants present in the smoke that is emitted out during the burning of fuel.

4. Industrial sector- This sector uses energy for a wide range of purposes, such as steam and cogeneration, process heating and cooling, lightning, heating and air conditioning for buildings

Types and Different Forms of Energy

  • Mechanical energy, electrical energy, optical energy, molecular, nuclear and atomic energy are the various forms of energy.
  • These forms of energy can change from one form to another but according to the law of conservation these forms of energy cannot undergo creation or destruction

 Kinetic Energy

  • Kinetic energy is the internal capacity of doing work of an object by virtue of its motion
  • E.= \(\frac{1}{2} mv^{2}\)
  • Kinetic energy depends upon the frame of reference moreover if the kinetic energy of the body decreases then work done is negative and vice-versa.

Potential Energy

  • Bodies that possess the energy by virtue of its position or configuration in a conservative force field are potential Energy.
  • Potential energy is a relative quantity
  • E= mgh

Solar Energy

  • Solar energy uses captured sunlight to basically create the photovoltaic power of the CSP i.e., Concentrated Solar Power.
  • It is the most eco-friendly form of energy as it uses solar panel and there is no emission of greenhouse gas.

Nuclear Energy

  • Nuclear energy originates by splitting of uranium atom via the process of fission
  • This generates heat to produce steam, which is used by a turbine generator to generate electricity.
  • Hence, nuclear energy is useful for the generation of electricity that we use in our day-to-day life.

Sound Energy

  • Sound energy is the form of energy which we living beings can hear. Only those waves that have a frequency of 16Hz to 20 kHz are audible to human beings. However, this range is an average and will slightly change from individual to individual.
  • Sound energy completely includes the waves of vibration and various terms such as frequency, wavelength, high pitch, low pitch, etc.
  • The simplest and most obvious use of sound energy is for hearing. Moreover, another way that we use sound waves to learn about our surroundings is SONAR i.e., Sound Navigation and Ranging which is used to map objects.
  • Sound energy needs a medium to travel across, such as air, water and metal. Sound energy always travels in waves and in all directions!

Advantages and Measurement of Energy

  • Saving energy has major 2 motives i.e., consumption and release of maximum types of energy produce lots and lots of smoke which directly harms our beautiful surrounding. Therefore, conserving energy produces a higher quality of survival while reduced emission results in an eco-friendly atmosphere which ensures a healthy environment. In addition, it provides a healthier planet and the second motive is that conserving energy helps in the sustainable development of our resources that we already have either in plentiful amount or limited stock.
  • Saving or conserving energy directly helps the population to save money! Also, cutting back on the amount of energy you use can reduce your energy bill. Hence energy conservation leads to dual savings which mean number one i.e., saves the resource energy and number two i.e., saves your hundreds of dollars that you spend on bills!

Measuring Energy

“you can’t compare apple and oranges!is the old saying that holds true for energy resources. We buy gasoline in gallons, woods in cords and natural gas in cubic feet. As they have different units then how can we compare them? Yes obviously we can, with British thermal units (Btu) and that’s how the energy contained in gasoline, wood and other energy resources can undergo measurement.

 One Btu is the quantity of thermal energy needed to increase the temperature of one pound of water around one degree Fahrenheit. A single Btu is small enough which means that suppose a wooden kitchen max if allowed burning completely, would give off about one Btu of energy. In a single day, the average American uses about 825.325 Btu we use the term quad (Q) to measure enough large quantities of energy. A quad is said as one quadrillion (1,000,000,000,000,000 or \(10^5\) ) Btu. The United States uses about one quad of energy approx. every 3.75 days. In 2007, the U.S. consumed 101.296 quads of energy.

Renewable And Non- Renewable Energy

Renewable energy is the energy that we collect from renewable resources. A Renewable resource basically means that a natural resource do not undergo depletion while its usage and has an ability of natural replenishment a human timescale including sources like sunlight, wind, rain, geothermal heat, waves and tides

For example- solar energy, wind energy, heat energy etc. Economic benefits of using renewable energy include; generating energy that produces no greenhouse gas emission from sources like fossil fuels that prevent the air pollution resulting in a healthy environment and highlighting the importance of fuels.

Non- renewable energy is the energy that we collect from the non-renewable resources that means a resource that cannot readily undergo replacement by natural means at quick enough to keep up with the ongoing consumption. For example coal, natural gas and oil.

FAQs about Energy

Q.1. Where does the energy of humans go when they die?

Answer. The pattern of flow of energy becomes thin and draws in towards the physical body when the person nears death and the chakras close from feet upwards in the cases of human death experience.

Q.2. Which is the cleanest energy?

Answer. Nuclear energy is one of the cleanest sources of energy emitting no greenhouse effect.

Q.3. Which is the dirtiest source of energy?

Answer. The pollution from fossil fuels is the single the biggest contributor to climate to climate change and the biggest dirty energy source is coal.

Share with friends

Customize your course in 30 seconds

Which class are you in?
Get ready for all-new Live Classes!
Now learn Live with India's best teachers. Join courses with the best schedule and enjoy fun and interactive classes.
Ashhar Firdausi
IIT Roorkee
Dr. Nazma Shaik
Gaurav Tiwari
Get Started

Leave a Reply

Notify of

Stuck with a

Question Mark?

Have a doubt at 3 am? Our experts are available 24x7. Connect with a tutor instantly and get your concepts cleared in less than 3 steps.

Download the App

Watch lectures, practise questions and take tests on the go.

Customize your course in 30 seconds

Which class are you in?
No thanks.