Question

The ammeter, shown below, consists of a $360\Omega$ coil connected in parallel to a $40\Omega$ shunt. Find the reading of the ammeter

• A. $0.35A$
• B. $0.4A$
• C. $0.25A$
• D. $0.02A$

Answer 1

Answer: (D)

As resistance $40\Omega$ and $360\Omega$ are in parallel, so their equivalent resistance is $360\Omega$. Which is further connected in series with $164\Omega$.
$\therefore$ Total resistance $=200\Omega$

$\therefore$ current $i=\frac{40}{200}=0.2A$
Now, from $A$ to $B$,
$40(i-i_1)=i_1\times 360$
$\Rightarrow 40(0.2-i_1)=360i_1$
$\Rightarrow 8-40i_1=360i_1$
$8=400i_1$
$\Rightarrow i_1=\frac{8}{400}=0.02A$