PHYS 2610
Assignment 2
due: Tue Feb 2, 2016
1. Equivalent resistance
Consider the circuit as shown in the diagram, with R1 = R2 = R .
a) How much current flows through resistor R3 and why?
b) What is the equivalent resistance between points A and D in this case?
c) The electric circuit in the figure is made from an infinite number of
squares of identical wire. The largest square has a side of length L, and
resistance R. Each subsequent smaller square connects the centres of each
side of the larger square. Using the simplification discovered in the
previous circuit, find the resistance between opposite corners of the largest
square.
2. Potato Circuit
A battery can be constructed out of a potato and two dissimilar metal
electrodes, as shown. A DMM is used to measure the potential
difference across the terminals of the potato battery, giving 0.83 V for
an open circuit, and 0.13 V with a 1 kΩ load.
a) Draw the potato battery test circuit, and analyze the above data to
determine a value of the potato cell’s output resistance.
b) How much current flows through the potato, and at what rate does
this current generate heat with the 1 kΩ load connected?