Question

Why can't the DC ammeter measure an alternating current?

• A. AC cannot pass through a DC ammeter
• B. AC changes its direction
• C. AC is virtual
• D. The average value of a complete cycle is zero

Hint:

Always remember — the average value of a full cycle of alternating current is zero, which makes standard DC ammeters unsuitable for AC measurement.

Answer 1

The Correct Option is D

A DC ammeter is designed to measure steady, unidirectional currents.
An alternating current (AC) continuously changes its direction, and the average value of a complete AC cycle is zero.
Since DC ammeters work based on average value detection for a steady current, they cannot measure the fluctuating nature of AC.