How Do Capacitors and Inductors Store Electric and Magnetic Energy?

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In a capacitor, energy is stored due to the separation of charges on its plates, with one plate holding excess positive charge and the other excess negative charge. This separation creates an electric field, which can be interpreted as the potential energy being stored either in the charges themselves or in the electric field throughout space. The energy density, which quantifies how energy is distributed in the electric field, is calculated using the formula that integrates the electric field squared over all space. This indicates that energy is primarily concentrated within the capacitor, while fringe fields are often neglected in calculations. The discussion highlights the relationship between charge separation, electric fields, and potential energy in capacitors, providing a foundational understanding of how electric energy is stored.
juhi
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hi
i am not exactly able to understand in which form or rather how electric and magnetic energy get stored in capacitor and inductor respectively... :shy:
 
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In a capacitor, one of the plates has excess positive charge and the other plate has excess negative charges. The negative charges want to fall towards the positive plate, just like we fall towards the earth.

As long as those charges are some distance apart (as long as an object is off the ground) there is stored up potential energy. It is our choice to say that the energy is "stored in the charges" or that the energy is "stored in the particle's field at all points in space", the mathematics can accomadate either interpretation.

I will let some one else explain an inductor for you.
 
thanks a lot..
 
that was a very nice explanation CROSSON...but when it is said that the space betn. plates is ""filled"" with electrical energy...how to explain this... :confused:
 
heman said:
that was a very nice explanation CROSSON...but when it is said that the space betn. plates is ""filled"" with electrical energy...how to explain this... :confused:

Since we are talking about stored potential energy when there is a charge separation, we can attribute that to the electric field, since whenever there is a charge separation there will be an electric field. Calculation of the total energy is given by
\int_{\hbox{All Space}} \frac{1}{2}\epsilon_0 \vec{E}^2 dV

so it makes sense to identify the integrand as the energy density as a function of position. And notice that the energy density is zero or very small at points where the electric field is zero or very small. In a capacitor we usually treat the electric field as being entirely inside the capacitor and neglect fringe fields, we consider that as being where all the energy is.
 
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