Resistivity chamber as shown in the picture, with a hemispherical hole (radius 4 cm) into which a powder sample to be examined is placed. After this, another electrode with a radius of 2 cm is pressed into the powder from above. What is the chamber constant Q of the device in the picture? (Chamber constant is the ratio of resistivity and resistance.) (V: 0.25 m)

Resistivity chamber as shown in the picture, with a hemispherical hole (radius 4 cm) into which a powder sample to be examined is placed. After this, another electrode with a radius of 2 cm is pressed into the powder from above. What is the chamber constant Q of the device in the picture? (Chamber constant is the ratio of resistivity and resistance.) (V: 0.25 m)