Question

Determine the current drawn from 12 V supply with internal resist 0.5 $\Omega$ by infinite network. Each resistor has 1 $\Omega$ resistance.

• A. 3A
• B. 2.7A
• C. 3.7A
• D. 4.2A

Answer 1

The correct option is C 3.7A

$\begin{array}{c}\Rightarrow Req=2+\frac{Req}{1+Req}\\ \Rightarrow Req\left(1+Req\right)=2\left(1+Req\right)+Req\\ \Rightarrow Req+Re{q}^2=2+3Req\\ \Rightarrow re{q}^2-2Req-2=0\\ \Rightarrow req=\frac{2\pm \sqrt{4+8}}{2}\\ =\frac{2\pm 2\sqrt{3}}{2}\\ =1+\sqrt{3}=2.7\Omega \\ \Rightarrow i=\frac{12}{2.7+0.5}=\frac{12}{3.2}=3.7A\\ Hence,theoptionCisthecorrectanswer.\end{array}$