Question

what is the total resistance?
a)1 ohm
b)2 ohm
c)3 ohm ​

Answer 1

$option : (a) \: 1 \: ohm$

Explanation:

$Resistance \: \: of \: \: 4 ohm \: \: and \: \: 2 ohm \: \: are \: \: in \: \: series, \\ then \: \: their \: \: equivalent \: \: resistance \\ = 4+2=6ohm \\now, \: \: \: the \: \: resistances \: \: of \: \: 2 \: ohm, 3 \: ohm \: \: and \: \: 6 \: ohm \: \: are \: \: in \: \: parallel, \\ then \: \: the \: \: equivalent \: \: resistance \: (r)\: \: of \: \: all \: \: of \: \: them \\ \frac{1}{r} = \frac{1}{2} + \frac{1}{3} + \frac{1}{6} \\ \frac{1}{r} = \frac{3 + 2 + 1}{6} \\ \frac{1}{r} = \frac{6}{6} \\ \frac{1}{r} = 1 \\ r = 1 \: ohm$