Answer:
C) 360 watts
Explanation:
We can find the power that is developed in the 10-ohm resistor by using this formula:
\(\boxed{P=\frac{V^2}{R} }\)
where:
- \(P\) = power
- \(V\) = voltage
- \(R\) = resistance
When the switch is in the open position, the current will only flow through the 10Ω and 20Ω resistors. Since both resistors are in parallel circuit and one of the rules of parallel circuit is: "All branches share the same voltage". This means:
\(\boxed{V_{source}=V_{10\Omega}=V_{20\Omega}=60\ V}\)
Now, we have enough data to find the power in the 10-ohm resistor:
- \(V_{10\Omega}=60\ V\)
- \(R_{10\Omega} = 10\ \Omega\)
\(\displaystyle P_{10\Omega}=\frac{V_{10\Omega}^2}{R_{10\Omega}}\)
\(\displaystyle=\frac{60^2}{10}\)
\(=\bf360\ watts\)
