The plates of capacitor are attached with non conducting spring of spring constant k. The initial separation between the plates is d and the spring is relaxed initially. Now the charges +Q and -Q is gradually given to the two plates then the capacitance of the capacitor will be ?

Attempt(my thinking): both plates will attract each other so they move x distance towards each other. I am really confused , what should be my approach. I just need a hint or a clue.


closed as off-topic by Aaron Stevens, Gert, ZeroTheHero, John Rennie, Ben51 Dec 9 '18 at 17:47

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  • $\begingroup$ Please note that we do not work out your homework problems for you here. What have you tried so far? What specific physics concepts are you struggling with? $\endgroup$ – Aaron Stevens Dec 8 '18 at 14:17

Without revealing the details (that's your homework!) you should think about this:

As the spring is being compressed, it is storing energy.

As the plates approach one another, the attractive force between them grows stronger.

Energy is conserved.

Now go to work!

  • $\begingroup$ Got it . ( but that’s not my homework...) $\endgroup$ – Apple Pie Dec 9 '18 at 3:07
  • $\begingroup$ Oh well... OK then! $\endgroup$ – niels nielsen Dec 9 '18 at 4:23

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