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. The energy of a charged capacitor is given by U = QV/2, where Q 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 capacitor. In this problem, you will derive two more formulas for the energy of a charged capacitor; 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 useful to recall the definition of capacitance, C = Q/V, and the formula for the capacitance of a parallel-plate capacitor, C=c04/d, where A is the area of each of the plates and d is the plate separation. As usual, co is the permittivity of free space. ▾ Part A Find the energy U of the capacitor in terms of C and Q by using the definition of capacitance and the formula for the energy in a capacitor. Express your answer in terms of C and Q. U= Submit ▾ Part C Part B Complete previous part(s) for Part A for Part A undo for Part A redo for Part A reset for Part A keyboard shortcuts for Part A help for Part A to A parallel-plate capacitor is connected to a battery. The energy of the capacitor is Uo. The capacitor remains connected to the battery while the plates are slowly pulled apart until the plate separation doubles. The new energy of the capacitor is U. Find the ratio U/Uo. > View Available Hint(s) Submit - Part D Request Answer %= for Part C for Part Cundo for Part C redo for Part C reset for Part C keyboard shortcuts for Part C help for Part C A parallel-plate capacitor is connected to a battery. The energy of the capacitor is Uo. The capacitor is then disconnected from the battery and the plates are slowly pulled apart until the plate separation doubles. The new energy of the capacitor is U. Find the ratio U/Uo. ▸ View Available Hint(s) for Part D for Part Dundo for Part D redo for Part D reset for Part D keyboard shortcuts for Part D help for Part D