Home
Class 12
PHYSICS
An ac ammeter is used to measure currnet...

An ac ammeter is used to measure currnet in a circuit. When a given direct current passes through the circuit. The ac ammeter reads 3 A. When another alternating current passes through the circuit, the ac ammeter reads 4A. Then find the reading of this ammeter (inA), if dc and ac flow through the circuit simultaneously.

A

3A

B

4A.

C

`7` A

D

5A

Text Solution

Verified by Experts

The correct Answer is:
D
Quantity of heat liberated in the ammeter of resistance R .
(i) Due to direct current of 3 ampere = `(3)^(2)` R / J)
(ii) Due to alternating current of 4 ampere
= [`(4)^(2)` R/J]
Total heat produced per second = `(3)^(2)`R / J + `(4)^(2)` / J = 25R / J
Let the equivalent alternating current be I virtual ampere, then
`I^(2)`R / J = 25R/J or I = 5A
Promotional Banner

Similar Questions

Explore conceptually related problems

A dc ammeter and a hot wire ammeter are connected to a circuit in series. When a direct current is passed through circuit, the dc ammeter shows 6 A. When ac current flows through circuit, the ac ammeter shows 8A. What will be reading of each ammeter if dc and ac current flow simulataneously through the circuit?

In the circuit shown, the reading of ammeter is:

The reading of the ammeter in the circuit below is

The reading of the ideal ammeter in the circuit is

In the circuit all the measuring instruments are ideal the reading of ammeter A_(2) is ……..

Assertion: when DC ammeter is used to measure current, then it measures average current flowing in the circuit . Reason : DC ammeter is based on heating effect of current .

Find the ammeter reading in the circuit

The current pasing through the ideal ammeter in the circuit given below is

The reading of ammeter in the circuit is