Where the energy to move electroscope leaves comes from?

[alikim]

Hi,

My question is about gold-leaf electroscope induction experiment as it's shown here: http://en.wikipedia.org/wiki/File:Electroscope_showing_induction.png

To spread out leaves you need to spend some energy, I'd like to know where it comes from

Thank you!

 

[tiny-tim]

welcome to pf!

hi alikim! welcome to pf!

the hand (in the picture) has to do more work to bring a charged rod near the plate than if the rod was not charged …

the extra energy is supplied by the hand

(which i assume is attached to a live human )

 

[alikim]

Thanks heaps!

 

[DrZoidberg]

If the electroscope is uncharged then the rod will be attracted to it and that means it takes less work to move a charged rod near the plate then an uncharged rod.
The energy comes from the electric charge and the voltage. Electric energy is charge times voltage.

 

[sardar]

I would like to address your question about the energy source for moving electroscope leaves. In the gold-leaf electroscope induction experiment, the leaves are initially spread out due to the repulsion between the like charges on the leaves. When a charged object is brought near the top plate of the electroscope, it induces a separation of charges in the leaves, causing them to move closer together. This movement of the leaves does not require any external energy source, as it is a result of the natural electrostatic forces between the charged objects and the leaves. Therefore, the energy to move the electroscope leaves comes from the electrostatic potential energy stored in the system. I hope this explanation helps to clarify the source of energy in this experiment.