What possible values of resultant resistance one can get by combining two resistances, one of value $2$ ohm and the other $6$ ohm?
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$R_1 = 2 ohm$, $R_2 = 6 ohm$
Case I: (parallel combination)
$\frac{1}{\text{R}}=\frac{1}{\text{R}_1}+\frac{1}{\text{R}_2}$
$\frac{1}{\text{R}}=\frac{1}{2}+\frac{1}{6}=\frac{4}{6}$
$\text{R}=\frac{6}{4}=1.5\ \text{ohm}$
CaseII: (Series combination)
$R = R_1+ R_2 = 2 + 6 = 8ohm$
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