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The topic of this problem is Electric Power.

Â The problem is to determine the missing quantity, the power, and

Â the second element.

Â We're giving at the power in the first element is equal

Â to 36 watts and its absorb power.

Â So we have 36 watts absorbed into element one.

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Is equal to the power divided by the voltage.

Â And that's equal to 36 watts divided by 12 volts.

Â And we also know that power is positive,

Â so that means that our current is going to be positive flowing back in

Â to the complex part of the circuit, so that if it were flowing through

Â this circuit in this manner will be flowing through this direction and

Â the positive of the current would go into the positive polarity across element one.

Â So it's the positive current hitting the positive

Â polarity if the element one voltage which is 12 volts.

Â And so, the current in this case is going to be 3 amps.

Â 3 amps of current flowing back into the complex circuit at the top of the circuit.

Â The problem is to determine what the power across the circuit element is and

Â whether it's absorb power or if it's supplied power.

Â We already know the current,

Â we determine that from the information were given about element one.

Â That is it had 12 volts across it with the polarity shown and

Â have 36 watts of the absorbed power.

Â We know that sensors absorb, it's a positive power.

Â And so that leads us to find the current.

Â Is in the direction toward the complex circuit and is a positive 3 amps.

Â And if that's the case, that positive 3 amps is also flowing through element two

Â from the bottom to the top.

Â And so for element two, P2 is going to be the current,

Â 3 amps and the voltage which is minus 4 volts.

Â The reason we chose minus 4 volts is because, if you look at the current,

Â the current is flowing into the bottom side of element two or

Â the polarity is negative, so the negative side of the 4 voltage drop

Â across element two gives us the minus sign in front of the four volts.

Â And so we end up in this case with 12 watts,

Â minus 12 watts of power, and

Â that means that we have 12 watts of

Â supplied power from element two.

Â