Question

Calculate the equivalent resistance when resistances of $2\Omega ,3\Omega$ and $6\Omega$ are connected in:​
a) Series ​
b) Parallel​

• A. Series : $1\Omega$
  Parallel : $11\Omega$
• B. Series : $11\Omega$
  Parallel : $1\Omega$
• C. Series : $36\Omega$
  Parallel : $1\Omega$
• D. Series : $11\Omega$
  Parallel : $36\Omega$

Answer 1

The correct option is B Series : $11\Omega$

Parallel : $1\Omega$
When connected in series, equivalent resistance is given by:
$R_s=R_1+R_2+R_3$
$R_s=2+3+6$
$R_s=11\Omega$

When connected in parallel, equivalent resistance is given by:
$\frac{1}{R_p}=\frac{1}{R_1}+\frac{1}{R_2}+\frac{1}{R_3}$
$\frac{1}{R_p}=\frac{1}{2}+\frac{1}{3}+\frac{1}{6}$
$\frac{1}{R_p}=\frac{(3+2+1)}{6}$
$R_p=1\Omega$