A friend who has just learned about dielectric insulators and capacitors is puzz

Question

A friend who has just learned about dielectric insulators and capacitors is puzzled and asks tor your help "Heres my problem." she says, "suppose f charge up a capacitor to an electrical energy level of 1 J. The plates are disconnected from everything and theres a vacuum between them. Now I place an insulator with dielectric constant R = 3 between the plates. Im pretty sure that the energy stored in the capacitor should go down but Im not sure by how much. But even after I figure that out, the real puzzle is this what happens to the energy that was lost? Where did it go?" Can you help her?

Explanation / Answer

Here ,

as dielectric constant , k = 3

for the isolated capacitor ,

charge on capacitor will be same

and new capacitance , C = 3 * Co

final energy = 1/(k) = 1/3

change in energy = 1/3- 1

change in energy = -2/3 J

the energy will go down by 2/3 J
------------------------------------------------
as the dielectric will be attracted by the capacitor ,

and energy will be transferred to the dielectric.

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---