Which term is used to name the difference in phase angle between two sinusoidal signals?

• A. Polyphase
• B. Proton
• C. Permeability
• D. Phase difference

Answer: (D)

The phase difference is the difference in phase angle between two sinusoidal signals. When two waves have the same frequency but start their cycles at different times, this difference in where they sit in their cycle is quantified as a phase difference, and it can be expressed in degrees or radians. If you write the signals as A1 sin(ωt + φ1) and A2 sin(ωt + φ2), the phase difference is Δφ = φ2 − φ1. A zero phase difference means they are in phase (peaks align); a positive value means one signal leads the other, while a negative value means it lags. This concept is fundamental in understanding how signals combine and how timing shifts affect constructive or destructive interference.