Created By : Vaibhavi Kumari

Reviewed By : Rajashekhar Valipishetty

Last Updated : May 07, 2023

To easily compute the energy density value, utilise the online Energy Density of Fields Calculator tool. To obtain the result in a shorter amount of time, input the electric field and magnetic field values in the calculator's fields and click the calculate button.

Choose a Calculation
Magnetic field (B):

What is Energy Density?

The total quantity of energy in a system per unit volume is known as energy density. The energy density is represented by the letter U. Magnetic and electric fields can store energy as well.

  • For a cell phone, a lithium-ion battery stores energy in the electric field.
  • A conventional magnet stores energy in the magnetic field.
  • Heat is produced by an electromagnetic wave (light), which stores energy in oscillating electric and magnetic fields and is used to warm humans.

Energy Density Formula

In a vacuum, the energy density of fields formula is; U = E² x (ϵ₀ / 2) + B² / (μ₀ x 2)

E = √[[U - B² / (μ₀ x 2)]/(ϵ₀ / 2)]

B = √[[U - E² x (ϵ₀ / 2)] x (μ₀ x 2)]

  • Where, B = magnetic field
  • E = electric field
  • U = energy density
  • Vacuum Permittivity ϵ₀ = 8.8541 x 10^-12 F/m
  • Vacuum Permeability μ₀ = 4π x 10^-7 H/m

How to Calculate Energy Density?

These are the basic steps for determining the energy density of fluids.

  • Step 1: Calculate the magnetic and electric field values.
  • Step 2: Multiply the electric field square by half of the vacuum permittivity constant.
  • Step 3: Divide the magnetic field's square by the double vacuum permeability constant.
  • Step 4: Check the energy density value by adding the two results.

How to Use the Energy Density Calculator?

The following is the procedure how to use the energy density calculator

  • Step 1: Input the magnetic field and x in the appropriate input fields.
  • Step 2: To acquire the result, click the "Calculate the Unknown" button.
  • Step 3: Finally, the output field will show the energy density value.

Examples of Electric Density

Question 1: The magnetic field in a particular region of space is 2.5 x 10^-2 T, whereas the electric field is 4 x 10^6 V/m. How do you calculate the total energy density of the electric and magnetic fields?



Electric field E = 4 x 10^6 V/m

Magnetic field B = 2.5 x 10^-2 T

Energy density U = E² x (ϵ₀ / 2) + B² / (μ₀ x 2)

U = (4 x 10^6)^2 x (8.8541 x 10^-12 / 2) + (2.5 x 10^-2)^2 / (4π x 10^-7 x 2)

= 70.83 + 248.67

= 319.50 J/m3

Therefore, the energy density is 319.50 J/m3

For more concepts check out to get quick answers by using this free tool.

FAQs on Energy Density

1. What is the EM wave's energy density?

The square of the amplitude of the electric (or magnetic) field determines the energy density of an electromagnetic wave.

2. What is a capacitor's energy density?

The energy density of a capacitor is the amount of energy stored per unit volume. The letter u symbolizes it. The joining of similar plates of charged capacitors always results in energy loss.

3. Which of the following has the maximum energy density?

Uranium has the highest energy density of any material. There are no byproducts of combustion with nuclear power, hence there are no pollutants in the atmosphere.

4. What is the definition of field energy?

The excitement of the space permeated by the electric field produces the energy of the electric field. It can be compared to the potential energy that a point charge placed in the field would get.

5. How do I calculate energy?

Energy = Power x Time is the formula that connects energy and power. The joule is the unit of energy, the watt is the unit of power, and the second is the unit of time.