Question

Calculate the resistance between the points X and Y in the network shown below.

[4 MARKS]

Answer 1

Formula for parallel connection: 1 Mark
Steps: 2 Marks
Answer: 1 Mark

We can redraw the given circuit as shown in Fig (i). The resistors of $3\Omega$ and $2\Omega$ are in series. Therefore, their equivalent resistance
$=3+2=5\Omega$

Now, the resistors of $5\Omega ,1\Omega$ and $5\Omega$ are parallel as shown in Fig. (ii).
Therefore, their equivalent resistance :
$\frac{1}{R}=\frac{1}{5}+1+\frac{1}{5}=\frac{1+5+1}{5}=\frac{7}{5}$
Or $R=\frac{5}{7}=0.71\Omega$
Hence, the resistance between X and Y is $0.71\Omega$.