Question

Alternating current can not be measured by direct current meters, because:

• A. alternating current can not pass through an ammeter
• B. the average value of current for complete cycle is zero
• C. some amount of alternating current is destroyed in the ammeter
• D. peak value of current is zero

Answer 1

Answer: (B)

the average value of current for complete cycle is zero

The alternating current changes its direction and magnitude, it becomes zero twice in a complete cycle. In one half cycle current flows in one direction and changes its direction for other half cycle. So, it is not possible by direct current meters to read such a high fluctuation in a second due to inertia and hence, no deflection accounted. Hence, alternating current can not be measured by direct current meters, because the average value of current for complete cycle is zero.