Question

The effective resistance across the points A and I is

• A. $2 \Omega$
• B. $1 \Omega$
• C. $0.5 \Omega$
• D. $5 \Omega$

Answer 1

Answer: (B)

$1 \Omega$

Answer 2

The given circuit reduces to equivalent resistance of 4 $\Omega$ each connected in parallel, hence
$40\,mm \frac{1}{R} = \frac{1}{4} + \frac{1}{4} + \frac{1}{4} + \frac{1}{4}$
$\Rightarrow \, 30\,mm \frac{1}{R} = \frac{4}{4}$
$\Rightarrow 30\,mm R = 1 \Omega$