Question

In the following circuit the value of total resistance between X and Y in ohm is

• A. $(1+\sqrt{3})R$
• B. $(\sqrt{3}-1)R$
• C. $\infty$
• D. 50 r

Answer 1

Answer: (A)

The correct option is A $(1+\sqrt{3})R$
let value of total resistance between X and Y in ohm is R.
because its infinite we can separate first three resisters from series and still the resistence will be R between A and B.
so there is a parallel R with 'r' as show in the figure.
$R=r+\frac{r\times R}{r+R}+r$
The above will form a quadratic equatio solving which you will get $R=(1+\sqrt{3})r$