An air-filled toroidal solenoid has a mean radius of 14.7 cm and a cross-sectional area of 5.02 cm2 . The current flowing through it is 12.5 A , and it is desired that the energy stored within the solenoid be at least 0.394 J . Average radius ra cross-sectional area Aa. What is the least number of turns that the winding must have?
Express your answer numerically, as a whole number, to three significant figures.

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