Question

Nine resistors each of resistance R are connected as shown in fig. The effective resistance between A and B is.

(A) (7/6)R

(B) R

(C) (3/5)R

(D) (2/9)R

Answer 1

The correct option (D) (2/9)R

Explanation:

it can be seen than three resistors each of value R are connected in parallel between points A, C and A, B and B,C.

Hence R equivalent between there points will be

{1/Req} = (1/R) + (1/R) + (1/R) = (3/R)

Req = (R/3)

Hence circuit can be drawn as

Hence RAB = (R/3) || {(R/3) + (R/3)}

= (R/3) || (2R/3)

= [{(R/3) × (2R/3)}/{(R/3) + (2R/3)}

= (2/9)R