The magnetic field on the axis of a circular current loop is far from uniform (it falls off sharply with increasing z). you can produce a more nearly uniform field by using two such loops a distance d apart .
find the field (b) as a function of z, and show that ∂b/∂z is zero at the point midway between them (z)

In a heat engine if 1000 j of heat enters the system the piston does 500 j of work, what is the final internal energy of the system if the initial energy was 2000 j? 1. write the equation 2.list out your known variables 3.plug the numbers into the equations 4.solve 5.write your solution statement that includes initial energy and final