Phasors Video Lessons

Concept

# Problem: Let us assume that a certain quantity I(t) changes over time as I(t) = I0cos(ωt). A phasor is a vector whose length represents the amplitude I0 (see the diagram (Figure 1) ). This vector is assumed to rotate counterclockwise with angular frequency ω, that way, the horizontal component of the vector represents the actual value i(t) at any given moment. In this problem, you will answer some basic questions about phasors and prepare to use them in the analysis of various AC circuits. At the moment shown in the diagram, which of the following statements is true? A) I2 leads I4 by πB) I2 lags I4 by 2πC) I2 leads I4 by π/2D) I2 lags I4 by π/2

###### FREE Expert Solution

The phase difference between angles of the two phasors is π (or 180°)

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###### Problem Details

Let us assume that a certain quantity I(t) changes over time as I(t) = I0cos(ωt). A phasor is a vector whose length represents the amplitude I0 (see the diagram (Figure 1) ). This vector is assumed to rotate counterclockwise with angular frequency ω, that way, the horizontal component of the vector represents the actual value i(t) at any given moment. In this problem, you will answer some basic questions about phasors and prepare to use them in the analysis of various AC circuits.

At the moment shown in the diagram, which of the following statements is true?

A) I2 leads I4 by π

B) I2 lags I4 by 2π

C) I2 leads I4 by π/2

D) I2 lags I4 by π/2