In the figure $AB$ is a wire of uniform cross - section and resistance $8 r$ . $A$ is an ideal ammeter with a resistance $r$ in series as shown in figure below. The cells are of Emf's $E & 2 E$ and internal resistance $r$ and $0$ respectively. Jockey $J$ can be moved freely on wire $AB$ making contact on wire at $C$ , length of wire is $1 m$ . Consider ammeter to be capable of measuring current in either direction of flow. (given that $E = 20 V; r = 2 Ω$ .Find the reading of ammeter when it shows maximum value: (Give integer value)

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Solution

For maximum reading of ammeter jockey should be connected at point $B$

$I = \frac{2 E}{r} = \frac{2 \times 20}{2} = 20 V$

Accepted answer : $20$

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For maximum reading of ammeter jockey should be connected at point B I=2Er=2×202=20 V Accepted answer : 20

For maximum reading of ammeter jockey should be connected at point $B$

$I = \frac{2 E}{r} = \frac{2 \times 20}{2} = 20 V$

Accepted answer : $20$