Aloop circuit has a resistance of r1 and a current of 1.9 a. the current is reduced to 1.5 a when an additional 3.1 ω resistor is added in series with r1. what is the value of r1? answer in units of ω.

Avertical clean glass piezometer tube has an inside diameter of d = 1 mm and is used to measure pressure in a horizontal pipe carrying water as shown. due to pressure in the pipe, the water at 20c rises into the tube to a height h. if the water pressure in the pipe is p = 500 pa gauge, estimate the height h: (a) without considering surface tension (b) with surface tension (capillary) effects. the contact angle  can be assumed at 30 deg