Circuit Solution via Incremental Quantities

Electricity and Magnetism Level 3

In the circuit shown below, \(r_1\) and \(r_2\) are resistors such that \(\frac{r_1}{r_2}=4\). If we connect a lamp as shown, the current through resistor \(r_1\) increases by \(\SI{0.1}{\ampere}\).

Find the current through the lamp (in amperes).