A15-ω resistor is connected in parallel with a 30-ω resistor. if this combination is now connected in series with an ideal 9.0-v battery and a 20-ω resistor, what is the current through the 15-ω resistor?

0.2 A

Explanation:

First of all, let's find the total resistance of the two resistors in parallel:

This combination is then connected in series with the other resistor, so the total resistance of the circuit is

Then we can calculate the total current in the circuit

This current flows through the resistor of 20-Ω, then it splits in the two branches of the 15-Ω and 30-Ω resistors.

The voltage drop across the resistor of 20-Ω is

So, the potential difference across the two resistors in parallel is

So, the current through the 15-Ω resistor is

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