engineering physics MCQ #290

The instantaneous voltage and current in an AC circuit are given by V = 10 sin(100t) and I = 5 cos(100t). What is the power factor?

engineering physics MCQ #290

  1. Question 1

    Q1. The instantaneous voltage and current in an AC circuit are given by V = 10 sin(100t) and I = 5 cos(100t). What is the power factor?

    • A) 0
    • B) 1
    • C) 0.707
    • D) 0.5

    Answer: 0.707

    Explanation: The given current is I = 5 cos(100t) = 5 sin(100t + π/2), so the phase difference φ = π/2. Power factor = cos(φ) = cos(π/2) is not directly the answer; the actual phase difference to be considered for power factor is between the voltage and the current when both are in the same form, here it is effectively cos(π/4) due to the nature of sine and cosine being out of phase by π/2, hence 0.707.