Q.

Equivalent resistance between the adjacent corners of a regular n-sided polygon of uniform wire of resistance R would be             [2023]

1 (n-1)Rn2  
2 (n-1)R(2n-1)  
3 n2R(n-1)  
4 (n-1)Rn  

Ans.

(1)

Suppose resistance of each arm is r, then r=Rn

Req(AB)=R1R2R1+R2

=r(n-1)rr+(n-1)r=r(n-1)rnr=n-1nr=(n-1)Rn2