Question

Phase difference between two voltages at frequencies above 10Hz can be measured using ___ .

• A. CRO
• B. Voltmeter
• C. X-Y plotter
• D. Multi meter

Hint:

Phase Measurement. Oscilloscopes (CROs) are the standard instrument for visualizing waveforms and measuring phase differences between signals, especially at frequencies beyond the range of mechanical plotters. Use dual-trace time comparison or Lissajous figures (XY mode).

Answer 1

The Correct Option is A

- Voltmeters and Multimeters measure voltage magnitude (RMS, average, or DC), not phase difference
- X-Y plotters are generally used for plotting one variable against another at very low frequencies (typically<1 Hz)
They are too slow for frequencies above 10 Hz
- A Cathode Ray Oscilloscope (CRO) is designed to display voltage waveforms as a function of time
By using a dual-trace CRO (displaying both voltages simultaneously) or by using the XY mode (Lissajous figures), the phase difference between two voltage signals can be accurately measured over a wide range of frequencies, including those well above 10 Hz (up to MHz or GHz depending on the CRO)
Therefore, a CRO is the appropriate instrument for measuring phase difference at these frequencies