Question

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

• A. Average value of current for complete cycle is zero
• B. A.C. Changes direction
• C. A.C. cannot pass through D.C. Ammeter
• D. D.C. Ammeter will get damaged.

Hint:

For A.C., the average value of the current over one complete cycle is zero. This is why a D.C. ammeter cannot measure A.C. correctly.

Answer 1

The Correct Option is A

Step 1: A D.C. ammeter is designed to measure the constant current that flows in a single direction. It operates by detecting the average value of the current. 
Step 2: Alternating current (A.C.) varies periodically with time. In one complete cycle of A.C., the current first flows in one direction and then reverses direction. This results in the average value of the A.C. current being zero over one complete cycle. 
Step 3: Since the D.C. ammeter measures the average value of the current, it would show zero for A.C. because the positive and negative half-cycles cancel each other out.