*Power
Dissipated in a Circuit*
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**Figure
1**

Find the power
dissipated in the 10 ohm resistor for the circuit (Figure 1).

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Solution:

First, we find the resistance
of the parallel section:

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Thus, the equivalent resistance
of the circuit is 4.55 ohms.

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The total current is 12 V/4.55
ohms = 2.64 A

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The voltage drop across the
3 ohm resistor is

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(2.64 A)(3 ohms) = 7.91 V

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The 10 ohm and the 6 ohm resistors
are in series, so these two equal 16 ohms:

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V_{16} = V_{para}
= 12 - 7.91 = 4.09 V

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I_{6} = I_{10}
= I_{16} = 4.09 V/16 ohms = 0.255 A

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The power dissipated in the
10 ohm resistor is