Two sinusoidal voltage of the same frequency are shown in the diagram. What is the frequency, and the phase relationship between the voltage?

Frequency in `Hz` phase lead of `N` over `M` in radius

Options

A. Frequency/Hz =0.4, phase lead of N over M in rad `s^(-1)`= `-(pi)/(4)`
B. Frequency/Hz =2.5, phase lead of N over M in rad `s^(-1)`= `-(pi)/(2)`
C. Frequency/Hz =2.5, phase lead of N over M in rad `s^(-1)`= `2(pi)/(2)`
D. Frequency/Hz =2.5, phase lead of N over M in rad `s^(-1)`= `-(pi)/(4)`

Answer

B

Explanation

the period of sinusoidal voltage , T=0.4s.
`f=1/T=1/(0.4)=2.5Hz`
N lags M by 0.1 s which is equivalent to `((0.1)/(0.4)) 2 pi or (pi)/(2) rad`.
Thus, the lead of N over M is `-(pi)/(2) rad`.