Question

A 50 Hz voltage is measured with a moving iron voltmeter and a rectifier type AC voltmeter connected in parallel. If the meter readings are VA and VB respectively. Then the form factor may be estimated as? (a) \frac{V_A}{V_B} (b) \frac{1.11V_A}{V_B} (c) \frac{\sqrt{2} V_A}{V_B} (d) \frac{πV_A}{V_B} The question was asked by my school teacher while I was bunking the class. My query is from Advanced Problems on Magnetically Coupled Circuits in portion Resonance & Magnetically Coupled Circuit of Network Theory Select the correct answer from above options network theory questions and answers, network theory questions pdf, network theory question bank, network theory gate questions and answers pdf, mcq on network theory pdf, gate network theory questions and solutions, network theory mcq Test , ies network theory questions, Network theory Questions for GATE EC Exam, Network Theory MCQ (Multiple Choice Questions)

Answer 1

The correct answer is (b) \frac{1.11V_A}{V_B} For explanation I would say: Form factor of the wave = \frac{RMS \,value}{Mean \,value} Moving iron instrument will show rms value. Rectifier voltmeter is calibrated to read rms value of sinusoidal voltage that is, with form factor of 1.11. ∴ Mean value of the applied voltage = \frac{V_B}{1.11} ∴ Form factor = \frac{V_A}{V_B/1.11} = \frac{1.11V_A}{V_B} .