A four-point probe (with probe spacing of 0.5 mm) is used to measure the resistivity of a type silicon sample. Find the resistivity of the sample if its diameter is 200 mm and its thickness is 50 µm. The contact current is 1 mA, and the measured voltage between the 
inner two probes is 10 mV.

A wire of diameter 0.800 mm and length 25.0 m has a measured resistance of 1.60 Ω. What is the resistivity of the wire?

A wire of diameter 0.800 mm and length 25.0 m has measured resistance of . What is the resistivity of the wire?     

Resistivity measurements on the leaves of corn plants are a goodway to assess stress and overall health. The leaf of a corn planthas a resistance of 2.2 M \Omega measured between two electrodesplaced 20 {cm} apart along the leaf. The leaf has a width of 3.0 cmand is 0.20 {mm} thick.

What is the resistivity of the leaf tissue?


Is this greater than or less than the resistivity of muscle tissuein the human body?