A very thin insulating annulus (a disk with a hole) has an outer radius R, and an inner radius of R/2. There is a charge Quniformly distributed over the surface of the annulus. The z-axis of the annulus would be perpendicular to the surface of this paper, located at the center of the disk. Consider the center of the disk to be the origin. A.Find the potential as a function of distance zfrom the annulus, along the axis.

1. what is the relationship between wavelength and the penetrating power of an electromagnetic wave? a) the penetrating power has no relationship to the wavelength. b) the penetrating power increases as the wavelength increases. c) the penetrating power decreases as the wavelength increases. d) the penetrating power decreases as the wavelength decreases. 2. as ice melts and turns into water, the speed of sound through the material would most likely do what? justify your answer. a) the speed would not change because the material is always water. b) the speed of sound would increase because the density of water is less than that of ice. c) the speed of sound would increase because energy is added to ice in order to make it melt. d) the speed of sound would decrease because sound travels faster through solids than liquids. 3.which of these waves need a medium to travel through? a) sound b) x-rays c) infrared rays d) visible light