Problem #2: Consider the following circuit, where one of the resistors is unknown. Note: the two parts of the problem are effectively independent; you can do them in any order. The "A" in a circle is an ideal Ammeter, which has NO VOLTAGE DROP across it. The Ammeter reads "0.0100 Amps"; this current is flowing to the right. 100 Ohms www R=? www www 200 Ohms 3V 川 A 圳 9V A) Given the above reading on the Ammeter, set up a system of equations for which one could solve for the unknown resistance R. You must be sure to uniquely define any variables in your equations, apart from R. B) Now you remove the Ammeter from the circuit, but you do NOT connect the two wires which originally went into the ammeter. (There is now a gap in the wire where the ammeter used to be.). Find the total power consumed by this (new) circuit. Give a numerical answer. Problem #1: Old televisions work by accelerating electrons inside of a large vacuum tube. When the electrons hit the fluorescent screen at the front they are moving so fast that they give off light. An electron needs to be going at a speed of 108 m/s to give off light, but suppose at one point in the tube the electron is only at 107 m/s, so it needs to be accelerated. The acceleration is provided by a pair of charged wire meshes. (The holes in the mesh are big enough to allow the electron to pass through.) The meshes are 10cm apart; the first mesh is at a potential Va, the second one is at a potential Vb. 10 m/s 10cm a Fluorescent screen A) Calculate the potential difference Va-Vb that will allow the electron to get from the initial speed of 107 m/s to the needed speed of 108 m/s, as it passes from the first to the second mesh. Be sure to consider and explain the sign of your answer. B) Find the average electric field between the meshes. If you don't have an answer for part A, give your answer here in terms of what that answer would be.