Question

In the diagram shown, all the wires have resistance R. The
equivalent resistance between the upper and lower dots
shown in the diagram is
(A) R/8
[C] 2R/5
[B)R
[D] 3R/8​

Answer 1

The equivalent resistance between upper and lower dots is 3R/8.

Let each wire has resistance = R

On connecting a cell between both the upper and lower end of circuit, all the wires will be connected with both the terminals.

Thus, all the 8 wires will be parallel.

Resistance of each segment =  R + R + R = 3R

1/ Res = 1/ 3R × 8

= 8/ 3R

or = 3R/8

Therefore, the equivalent resistance between upper and lower dots is 3R/8.