"a jack-in-the-box is a toy in which a figure in an open box is pushed down, compressing a spring. the lid of the box is then closed. when the box is opened, the figure is pushed up by the spring. the spring in the toy is compressed 0.070 meter by using a downward force of 12.0 newtons.

identify one form of energy to which the elastic potential energy of the spring is converted when the figure is pushed up by the spring."

To understand the behavior of the electric field at the surface of a conductor, and its relationship to surface charge on the conductor. a conductor is placed in an external electrostatic field. the external field is uniform before the conductor is placed within it. the conductor is completely isolated from any source of current or charge. part a: which of the following describes the electric field inside this conductor? it is in the same direction as the original external field. it is in the opposite direction from that of the original external field. it has a direction determined entirely by the charge on its surface. it is always zero. part b: the charge density inside the conductor is: 0non-zero; but uniformnon-zero; non-uniforminfinite part c: assume that at some point just outside the surface of the conductor, the electric field has magnitude e and is directed toward the surface of the conductor. what is the charge density η on the surface of the conductor at that point? express your answer in terms of e and ϵ0