Question

Copy of Best of Homework for Glancoli, Physics: Principles with Applications, 70 Martyna & © <Ch 17 HW Energy in Capacitors and Electric Fields 10 of 25 Constanta Learning Goal: To be able to calculate the energy of a charged capacitor and to understand the concept of energy associated with an electric field. . Use the formules from The energy of a charged capachor is given by U = QV/2, where is the charge of the capacitor and V is the potential difference across the capacitor The energy of a charged capacitor can be described as the energy associated with the electric field created Inside the capacito A parallel-plate capacitor has area and plate separation d, and it is charged so that the electric field inside is the problem introduction to find the energy of the capacitor Express your answer in terms of A, d, E, and appropriate constants. View Available Hits) ed... V0 | ΑΣφ # O ? In this problem, you wil derive two more formulas for the energy of a charged capachor you will then use a parallel-plate capacitor as a vehicle for obtaining the formula for the energy density associated with an electric field. It will be used to recall the definition of capacitance. V. and the formula for the Capacitance of a paralel plate capacitor, Submit C= Ald, where is the area of each of the plates and is the plate separation. As usun, is the permitivity of trees - Part 6 Find the energy density of the electric field in a paralel plane capacitor. The magnitude of the electric field inside the capacitors Express your answer in terms of Eand appropriate constants. View Available Hints) 80 AED Submit Provide Feedback

Answer 1

F)

We have the energy stored in a capacitor as,

IT-

By definition, the charge stored in a capacitor is,

$Q=CV$

The capacitance of a parallel plate capacitor is,

AEO

Also,

Since the field inside the capacitor is uniform and we can write the potential as,

V = Ed

Substituting for charge, capacitance and potential in the expression of energy, we get,

2 2d

G)

Volume inside the capacitor is,

T= Ad

Therefore, energy density is,

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