text: Measuring this value for a semiconductor is done with a four-point probe and allows one to determine the concentration of impurities.
full_question: Measuring this value for a semiconductor is done with a four-point probe and allows one to determine the concentration of impurities. A device first fabricated at HP Labs using a thin film of titanium dioxide has a value for this quantity that depends on the history of current in the device. After the turn-on voltage, an ideal diode has a value of zero for this quantity. An unknown value of this quantity can be found by setting up a diamond shape and adjusting until there's no voltage drop across the bridge, a method popularized by Charles (*) Wheatstone. This quantity is the real part of impedance. For a wire this quantity equals rho times length over cross-sectional area, where rho is the inverse of the conductivity. This quantity adds when its namesake circuit elements are placed in series. For 10 points, what quantity is equal to voltage divided by current, by Ohm's law?
first_sentence: Measuring this value for a semiconductor is done with a four-point probe and allows one to determine the concentration of impurities.
raw_answer: resistance [or R; or resistivity or rho until "impedance" is read] 