Wheatstone bridge is often used to measure the electrical resistance. This circuit is built with two or three known resistors, one unknown resistor, and one variable resistor connected in the form of a "bridge" (see figure below, left). In this problem, however, we are going to use known resistors. Assume that resistors P, Q, R, and S all have a resistance of 200 Ω and the battery has an emf of 10.0 V. The arrow in the middle represents an ammeter, and the current through it is Is. Note: yes, I know we have not dealt with these kinds of circuits. Explore a little. Look at Section 26.2, and specifically Example 26.6. In reality, this circuit is not any different than any other circuit: Set up, but do not solve all the possible loops and junction rules that would allow you to solve for the unknown currents. Hint: does the number of equations match the number of unknowns? The central wire is now removed, as shown in the figure below, right. Everything else stays the same. Solve for equivalent resistance and the current through each resistor.
Ri
3√z