# An electricity and magnetism problem by Jonathan Schirmer

**Electricity and Magnetism**Level 4

Consider a cube made of six conducting plates. One is held at a potential of \( 20 \) \( V \) and the other five are grounded. The potential at the center of the cube can be expressed in Volts as \( \frac{a}{b} \) where \( a \) and \( b \) are coprime positive integers. What is the value of \( a+b \)?