Question

In the given circuit, a galvanometer with a resistance of 70$\Omega$ is converted to an ammeter by a shunt resistance of 0.05$\Omega$, the total current measured by this device is

• A. 0.88 A
• B. 0.77 A
• C. 0.55 A
• D. 0.99 A

Answer 1

The correct option is D 0.99 A

The equivalent circuit of given circuit is given by
Here, $R_s$ = $\frac{R_g{r}_s}{R_g+r_s}$=$\frac{70\times 0.05}{70+0.05}$
$R_s$= 0.0499$\Omega$ = 0.05$\Omega$
The total resistance in the circuit
R=$R_s$ + 5$\Omega$ = 5.05$\Omega$
The current measured by the device
$I=\frac{V}{R}$=$\frac{5}{5.05}$ = 0.99A