JEE Main · 2004 · 24 Apr 2004 · Offline · Alternating Current

Alternating current can not be measured by D.C. ammeter because

(A)A.C. cannot pass through D.C.
(B)A.C. changes direction
(C)average value of current for complete cycle is zero✓ Correct
(D)D.C. ammeter will get damaged.

Answer: (C)

Solution

A D.C. ammeter responds to the average current. Over one full cycle an alternating current spends equal time positive and negative, so its average across the cycle is zero and the meter reads nothing. That is why alternating current cannot be measured with a D.C. ammeter.

JEE Main · 2004 · 24 Apr 2004 · Offline · Single correct option

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