Finding charge on sphere using energy

1. The problem statement, all variables and given/known data
a) What charge would need to be placed on a metal sphere such that the electric field produced stored a total of 50 J if the radius of the sphere was 18 cm?
b) How much work would need to be done to reduce the radius to 9 cm, assuming the sphere is (mechanically) easily compressible?

2. Relevant equations
V=(4/3)pi r2

3. The attempt at a solution
Not sure where to tackle this problem…

Leave a Reply

Name *
Email *