The effective resistance of two resistors in parallel is ` (12)/(7) Omega`. If one of the resistors is disconnected the resistance becomes `4 Omega`. The resistance of the other resistor is

Options

A. `4Omega`
B. `3Omega`
C. `(12)/(7)Omega`
D. `(7)/(12)Omega`

Answer

B

Explanation

Given, `R_(1)= 4Omega` Using the relation for parallel combination of two resistors
`(R_(1)R_(2))/(R_(1)+R_(2))=(12)/(7), R_(1)=4 Omega, R_(2) = ?`
or `" " (4R_(2))/(4+R_(2))=(12)/(7)`
or `28R_(2)=48+12 R_(2)` or `16 R_(2)=48 rArr R_(2) = 3 Omega`