Question

If ammeter has zero resistance then –

• A. Reading of ammeter is $\frac{\varepsilon}{6R}$
• B. Reading of ammeter is $\frac{\varepsilon}{7R}$
• C. Reading of ammeter is $\frac{\varepsilon}{8R}$
• D. Reading of ammeter is $\frac{\varepsilon}{9R}$

Answer 1

Answer: (B)

Reading of ammeter is $\frac{\varepsilon}{7R}$

Answer 2

Equivalent circuit

$\Downarrow$

R_eq = $\frac{2R}{3} + \frac{R}{2}$ = $\frac{7R}{6}$

i = $\frac{\varepsilon}{R_{eq}}$

$\Downarrow$

Using Kirchoff's first law current through

AB = $\frac{3\varepsilon}{7R} - \frac{2\varepsilon}{7R} = \frac{\varepsilon}{7R}$