Q.

A wire of resistance R is bent into a triangular pyramid as shown in figure with each segment having same length. The resistance between points A and B is R/n. The value of n is:          [2025]

1 16  
2 14  
3 10  
4 12  

Ans.

(4)

As, r=R6

(As balanced wheat stone bridge is formed)

Now, Equivalent resistance between A and B can be written as

Clearly, R1=r6

So, RAB=R12R12R1

 1RAB=1R1+12R1+12R1=42R1=2R1

 RAB=R12=r12