When an electrical current is flowing through an electromagnet, it encounters resistance. The resistance in the electromagnet can be reduced by A.
using a thicker wire of the same material

B.
connecting both ends of the wire of the positive terminal

C.
using a battery with higher voltage

D.
removing the core from the looped wire

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