How do the magnetic fields of Uranus and Neptune suggest that the mantles inside those planets are fluid?

An electric current in a wire will push or pull on a permanent magnet. which statement best explains how an electric current creates an electromagnetic force on another magnet?

The rigid beam is supported by the three suspender bars. bars ab and ef are made of aluminum and bar cd is made of steel. if each bar has a cross-sectional area of 450 mm2, determine the maximum value of p if the allowable stress is (σallow)st = 200 mpa for the steel and ( σallow)al = 150 mpa for the aluminum. est = 200 gpa and eal = 70 gpa.

Find the magnetic field a distance r from the center of a long wire that has radius a and carries a uniform current per unit area j in the positive z direction.