If the circuit a potential difference of `3V` is required between the point `C and D`. Find the value of resistance `r_(2)`

Answer

`2 Omega`

Explanation

Here, `IR_(2) = 3 "volt" or I = (3)/(R_(2))`
`I = (epsilon)/(R_(1) + R_(2) + r) = (12)/(5 + R_(2) + 1) = (12)/(6+ R_(2))`
`:. (3)/(R_(2)) = (12)/(6 + R_(2)) or 18 + 3 R_(2) = 12 R_(2)`
or `R_(2) = 2 Omega`