Question

What is φ in terms of voltage?

(a) φ=cos^-1V/VR

(b) φ=cos^-1V*VR

(c) φ=cos^-1VR/V

(d) φ=tan^-1V/VR

The question was asked in quiz.

The query is from Resistance and Inductance in Series in portion Single Phase Series Circuits of Basic Electrical Engineering

Answer 1

Right choice is (c) φ=cos^-1VR/V

Easiest explanation: From the voltage triangle, we get cosφ= VR/V.

Hence φ=cos^-1VR/V.