Heat in the atmosphere always moves which way?

Along, straight wire with 3.0 a current flowing through it produces magnetic field strength 1.0 t at its surface. if the wire has a radius r, where within the wire is the field strength equal to 36.0% of the field strength at the surface of the wire? assume that the current density is uniform throughout the wire

In a voltaic cell, electrons flow from the (positive/negative) to the (positive/negative) terminal.

Which accurately compares concave and convex lenses?