Question

A 33 nf capacitor is connected to a 9.00 V battery and fully charged. The capacitor is then disconnected from the battery, an an insulator having a dielectric constant is inserted between the plates of the charged capacitor. What is the energy stored in the capacitor with the dielectric inserted?

Answer 1

The energy stored in a capacitor,

And

Putting this back

When 33nf capacitor is connected to 9V battery the charge stored in capacitor

As we insert a insulator with dielectric constant K(dielectric constant is not provided in question so just put numerical values replacing K if you want.), ​​​the Capacitance of capacitor increases K times

So new Capacitance of capacitor,

The same way we figured out earlier, energy stored in capacitor would now be

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