# I Inductance of a metal sphere (1 Viewer)

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#### John Shillington

Hey everyone this is my first thread i was wondering how you calculate the inductance of a solid sphere. Say a sphere for example of 5cm diameter with electrical contacts on opposing sides 0.5 cm in diameter.
Any help would be much appreciated

#### phyzguy

The simplest way is to assume a current I flowing through the sphere. Then, given this I, calculate the magnetic field everywhere. Then, calculate the total magnetic field energy by integrating B^2/(2*μ0) over all space. This should give an answer proportional to I^2. The total inductive energy is L*I^2/2, so you can calculate L by equating the total magnetic field energy to the inductive energy L I^2/2.

• berkeman and tech99

#### John Shillington

Thanks for your reply, it was informative.

• berkeman

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