Q. If you are provided three resistances $ 2\,\Omega ,\,3\,\Omega $ and $ 6\,\Omega$. How will you connect them, so as to obtain the equivalent resistance of $ 4\,\Omega . $ ?
Delhi UMET/DPMTDelhi UMET/DPMT 2003
Solution:
In the given question in option (c),
$ 3\,\Omega $ . and $ 6\,\Omega $ resistances are in parallel,
hence equivalent resistance is
$ \frac{1}{R}=\frac{1}{6}+\frac{1}{3}=\frac{9}{18} $
$ \Rightarrow $ $ R=2\,\Omega
$ The two $ 2\,\Omega $ . resistances are now connected in series,
hence equivalent resistance is
$ R=2\,\Omega +2\,\Omega =4\,\Omega $
Note: The value of the equivalent resistance of the resistances connected in parallel is less than the value of the smallest resistance among those resistances.
