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A circuit contains three resistors connected in parallel. The value of R1 is 2 K , the value or R2 is 6 K , and the value of R3 is 10 K . If the supplied voltage is 100 VDC, what is the total power in the circuit?

A. 2.18 W

B. 8.18 W

C. 7.67 W

D. 4.24 W

(Can someone help me understand how to get the answer?)

Respuesta :

Answer: C. 7.67 W

Explanation:

Firstly, we are told the three resistors are connected in parallel, this means we have to use the following equation to find the total resistance [tex]R[/tex] of the circuit:

[tex]\frac{1}{R}=\frac{1}{R_{1}}+\frac{1}{R_{2}}+\frac{1}{R_{3}}[/tex]  (1)

Where: [tex]R_{1}=2k\Omega[/tex], [tex]R_{2}=6k\Omega[/tex], [tex]R_{3}=10k\Omega[/tex]

Solving (1):

[tex]\frac{1}{R}=\frac{1}{2k\Omega}+\frac{1}{6k\Omega}+\frac{1}{10k\Omega}[/tex]  (2)

[tex]\frac{1}{R}=\frac{23}{30k\Omega}[/tex]  (3)

[tex]R=1.3043k\Omega}=1304.34\Omega[/tex]  (4)  This is the total resistance of the circuit

On the other hand, the total power [tex]P[/tex] of this circuit is given by the following equation:

[tex]P=\frac{V^{2}}{R}[/tex]   (5)

Where [tex]V=100V[/tex] is the total voltage of the circuit.

Solving:

[tex]P=\frac{(100V)^{2}}{1304.34\Omega}[/tex]   (6)

Finally:

[tex]P=7.67V\Omega=7.67W[/tex]   (7) This is the total power of the circuit in Watts (W)