A resistor with an unknown resistance is connected in parallel to a 13 Ω resistor. When both resistors are connected in parallel to an emf source of 23 V, the current through the unknown resistor is measured with an ammeter to be 4 A. What is the resistance of the unknown resistor? Answer in units of Ω.

Water is siphoned from a large tank and discharges into the atmosphere through a 50-mm diameter tube. the end of the tube is b = 2.6 m below the tank bottom which is a = 6.7 m deep, and viscous effects are negligible. determine the maximum height h over which the water can be siphoned without cavitation occurring. atmospheric pressure is 101.4 kpa, and the water vapor pressure is 1.79 kpa (absolute). report your answer in meters to two decimal places.