Which of the following statements are TRUE? 

1. Phasors are an efficient method of analyzing AC circuits when the frequencies are the same. Thus on a single phasor diagram, all the plotted phasors  represent sinusoids of the same frequency.  All phasors on the same phasor diagram are considered to rotate at the same angular frequency in a counterclockwise direction. 

2. In the phasor diagram, everything is plotted on a coordinate system and phasors can be treated in a similar fashion to  vectors. Thus phasor diagram must be drawn to scale and their resultants can be found by simply applying vector algebra. 

3. Vectors have magnitude and direction and thus the phasors on a phasor diagram are normally defined by their length and also  by their angles with respect to a specific reference phasor. 

4. The "reference phasor" is one of the circuit phasors that chosen to lie on the x axis of the phasor diagram, pointing to the right. The angle between two phasors is the same as the phase angle between the two sinusoids.

5. According to standard, the length of a phasor is equal to the rms value of the equivalent sinusoid  (unless it is specifically stated otherwise). 

6. In the diagram below, the purple phasor is equal to Vx + Vy.
7. In the diagram below, Vx lags Vy by angle θ.

8. The scale in the diagram below does NOT apply to the resultant vector.