The problem involves calculating the charge required on a metal sphere to store a specific amount of electric energy, as well as the work needed to change the sphere's radius. The subject area includes electrostatics and energy storage in electric fields.
Participants are actively exploring different equations and concepts related to the energy stored in a charged sphere. Some have proposed equations and calculations, while others are questioning the validity of these approaches and the assumptions made. There is no explicit consensus on the correct method yet.
Participants note the importance of understanding whether the sphere is uniformly charged, the nature of the charge distribution, and whether it is a conductor or insulator. These factors are critical for determining the correct approach to the problem.
Simon Bridge said:How much work to get the first smallest bit of charge onto the sphere (from infinity)?
How about the next bit?
The bit after that?
... spot the pattern.
Either that or look up the equation for the amount of energy stored in a charged metal sphere.
Simon Bridge said:So how can you tell if it is the right equation?
i.e. read the book carefully: what exactly does it say this is the energy of?
... is that exactly what it says?need_aca_help said:Energy stored by a charged sphere
Simon Bridge said:... is that exactly what it says?
Not just what's written down - there is usually a diagram as well.
i.e. is the sphere uniformly charged? Is the charge distributed through the whole volume or just on the surface? Is the sphere a conductor or an insulator?
If you cannot narrow this down you will have to do some calculus.