A student has two resistors- `2Omega` and `3Omega` She has to put one of them in place of R2 as shown in the circuit. The current that she needs in the entire circuit is exactly 9A. Show by calculation which of the two resistors she should choose.

Explanation

The overall current needed = 9A. The voltage is 12V Hence by Ohm’s Law V=IR, The resistance for the entire circuit = `12//9 = 4//3 Omega. = R R_(1)" and "R_(2)` are in parallel. Hence,` R=(R_(1) R_(2))/(R_(1) + R_(2)) = 4R2/(4+R_(2)) = 4//3 R_(2) = 2Omega`