Question

Two resistance wires on joining in parallel the resultant resistance is 6/5 ohms. One of the wire breaks the effective resistance is 2 ohms. The resistance of the broken wire is

Answer: 2 ohm

Answer 1

Parallel so 1/R(total) = 1/R1+1/R2
R(total) = R1R2/(R1+R2)
It is 6/5
When one wire is broken R1 act as series let the broken wire be R2 so now R1 = 2 ohm

So 6/5 = 2(R2)/(2+R2)

Solving 4R2 = 12
So R2 = 3

Answer is 3 not 2 .

2 don't even satisfy the equation of parallel resistance