Practice portal › Alternating Current › Alternating Quantities: RMS and Mean

Alternating current cannot be measured by a D.C. ammeter because

Asked in AIEEE 2004 · Measuring AC quantities

• (1) a.c. cannot pass through a D.C. ammeter
• (2) a.c. changes direction
• (3) the average value of current over a complete cycle is zero
• (4) the D.C. ammeter will get damaged

Step-by-step solution

Why the other options are wrong

• (1) A.c. does flow through the meter; that is not the issue.
• (2) True as a fact, but it is the zero average, not the change of direction itself, that gives no deflection.
• (4) The meter is not damaged; it simply reads zero.

Reading this solution needs no sign-in. You only sign in to practise against the clock and keep your progress.