Задача 30971.

Two parallel-connected flat capacitors, whose capacitances C1 = 200 pF and C2 = 100 pF, were charged, after which the source was turned off. Then the dielectric was removed from the first capacitor (e1 = 4). As a result, the voltage on the capacitors became equal to 80 V. Find: the energy of the second capacitor (d2 = 2 mm, S2 = 100 cm^2) before removing the dielectric from the first capacitor; volumetric density of this energy.

Detailed solution with a brief record of the conditions, formulas and laws used in the solution, derivation of the calculation formula and answer.
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