What are the radiation surface and space resistances? How are they expressed? For what kind of surfaces is the radiation surface resistance zero?

Throughout the voltage divider experiment a student observes the current never changes as long as the power supply voltage is never changed. They would like to make a plot to determine if the potentiometer is linear with respect to wiper position. Which of the following plots allows for that determination by giving a straight line if the device is linear? All of these plots will give a straight line if the potentiometer is linear. O A plot of V₁ - V₂ (vertical axis) vs (horizontal axis). A plot of (vertical axis) vs (horizontal axis). O A plot of V₁ + V₂ (vertical axis) vs 4 (horizontal axis). O A plot of V₁ (vertical axis) vs l₁ (horizontal axis).

A long rod, radius R, that has uniform positive charge density p is spun around its central axis with angular velocity w, as shown below, so that the charges follow circular paths centered on the axis. Current is the flow of charge, so we have rings of current of varying radius r. You may want to review the following relationships: Current density J = dI/dA = pv (from chapter 24!) and v=wr (from PHY 204!) This means that the rotating rod of charge is equivalent to a non-uniform current density J = pwr, where the current is circulating around the axis and r is the radial distance from the axis. Note this has the same symmetry as the solenoid (current flowing in circles, field lines straight and parallel to the axis). The difference is that this is like having many nested solenoids, and as we head out from the axis, we see more and more current. R I will walk you through the steps for using Ampere's law to find the magnetic field inside the rod. (a) Draw a diagram of a cross section of…

The radii of the two concentric conductive spheres are r1 and r2>r1. The resistivity of the material between the spheres is p. If the total current I from the inner sphere to the outer sphere, Find the electric potential difference between the spheres.Give your answer in terms of (r1, r2, p, I).