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An isolated, parallel‑plate capacitor carries a charge Q . If the separation between the plates is doubled, the electrical energy stored in the capacitor will be:a. Unchanged.b. Halved.c. Doubled.d. Quartered.e. Quadrupled.

Respuesta :

Answer:

option C

Explanation:

Given,

Change on the capacitor = Q

Separation is doubled

Energy stored in the capacitor,E = ?

we know,

[tex]E = \dfrac{Q^2}{2C}[/tex]

and [tex]C = \dfrac{\epsilon_0A}{d}[/tex]

now,

[tex]E = \dfrac{Q^2}{2\epsilon A}\ d[/tex].......(1)

where d is the separation between the two plates.

now, when the separation is doubled

[tex]E' = \dfrac{Q^2}{2\epsilon A}\ (2d)[/tex]

[tex]E' = 2(\dfrac{Q^2}{2\epsilon_0 A}\ d)[/tex]

From equation (1)

  E' = 2 E

Hence, the energy stored in the capacitor is doubled if the separation is increased.

The correct answer is option C.