Third Period Math Applications Flashcards

1
Q

Which Law states that all current entering a node, must leave said node? What is this law also commonly referred to?

A

Kirchoff’s Current Law.

Conservation of Charge.

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2
Q

Which Law states that the algebraic sum of all voltages within a closed loop must equal 0? What is this law also commonly referred to?

A

Kirchoff’s Voltage Law.

Conservation of energy.

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3
Q

How is it determined that two loads are connected in series?

A

They experience the same current.

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4
Q

What happens in an unbalanced 3 wire circuit when the neutral is open circuited?

A

The loads act as if they are in series and the higher voltage drop is taken by the load of larger impedance.

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5
Q

If current flows through a resistor from right to left, which end of the resistor has a positive polarity?

A

The left end.

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6
Q

Is it possible for a neutral wire to act as a source when powering a load?

A

Sort of, in an unbalanced 3 wire circuit, the neutral will be a voltage drop for one load and a voltage rise for the other; So - while not a source - it does provide some energy to the load.

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7
Q

What is a hypotenuse?

A

The longest side of a right angle triangle, opposite the right angle.

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8
Q

Why might trigonometry be quite useful in the field?

A

Complex and semi complex pipe and tubing bending.

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9
Q

In a series resonant circuit can resistance be added to net reactance to find impedance?

A

No, they must be added vectorally using the pythagorean theorum.

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10
Q

What is power factor and how is it determined?

A

The ratio between power and apparent power.

P/S, R/Z, Cos(theta).

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11
Q

What is a composite drawing?

A

One which contains multiple drawings to illustrate a larger picture. We use these in impedance and power triangles.

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12
Q

If a facility is power factor corrected, is the amount of active power increased?

A

No, watts should remain constant in a power factor correction.

The addition of a capacitor bank will only reduce system inductive VARs.

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13
Q

In a phasor diagram, If current is referenced, a voltage phasor exists at a phase angle of 60 degrees. Does this phasor represent an inductive or capacitive load? Does current lead or lag the voltage?

A

Inductive.

Current lags the voltage.

Lagging circuit.

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14
Q

In a phasor diagram, how is the passage of time imagined?

A

The phasors rotate, counterclockwise.

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15
Q

Are inductive vars always negative in a parallel RLC circuit?

A

No, they are simply out of phase. We draw them on the south of our cartesian plane to illustrate that they are 180 degrees out of phase with capacitive vars.

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16
Q

When a phase angle, source voltage and source current are known, how is reactive power determined?

A

Sine (theta) multiplied by apparent power.

The sine function is a ratio of opposite/hypotenuse.

17
Q

What is the easiest way to check work and solve problems using a phasor diagram?

A

Add phasors tip to tail and visually determine if the solution makes sense.

18
Q

What is an indirect proportion?

A

A comparison of two ratios. When one quantity is multiplied by c, the other is multiplied by c-1 .

A common inverse proportion we encounter is turns ratio vs current ratio in a transformer.