25.69 ... CP Two cylindrical cans with insulating sides and conducting end caps are filled with water, attached to the circuitry shown in Fig. P25.69 , and used to determine salinity levels. The cans are identical, with radius r = 5.00 cm and length L = 3.00 cm. The battery supplies a potential of 10.0 V, has a negligible internal resistance, and is connected in series with a resistor R = 15.0 0. The left cylinder is filled with pure distilled water, which has infinite resistivity. The right cylinder is filled with a saltwater solution. It is known that the resistivity of the saltwater solution is determined by the relationship p = (so/s) 2 . m, where s is the salinity in parts per thousand (ppt) and so = 6.30 ppt. (a) The ammeter registers a current of 484 mA. What is the salinity of the saltwater solution? (b) The left cylinder acts as a capacitor. Use Eq. (24.19) 3 for its capacitance. How much charge is present on its upper plate? Note that pure water has a dielectric constant of 80.4. (c) At what rate is energy dissipated by the saltwater? (d) For what salinity level would the 15.0 0 resistor dissipate half the power supplied by the battery? Figure P25.69 R L 3Capacitance of a Dielectric constant Area of each plate parallel-plate F... A A ........ Permittivity = KEQ capacitor, dielectric .* = E between plates C = KCo = KEo d.... Capacitance .. Electric Distance between plates without dielectric constant (24.19)